≡× MENU

• Interior
• Windows
• Walls
• Projects
• Buildings

Drawing scales according to GOST. Placing images on drawings. Scales of drawings. Measuring distances with a millimeter ruler

But it is not always possible to use a 1:1 scale due to the fact that the size and complexity of the products shown in the drawing are different; some products (for example, machine tools) are so large that their images on a scale of 1: 1 would require huge sheets of paper, drawing boards of the appropriate size, measuring rods, etc.; it is not possible to do all this. Some products (for example, watch movements) are so small that it is almost impossible to depict them on a scale of 1: 1 and, in addition, from such an image it is sometimes impossible to understand the shape and size of not only individual elements, but even entire parts.
In such cases, product images are either reduced or enlarged.
GOST 3451-59 establishes the following scales of images in drawings, as well as their designation:

If there is a need for a greater reduction or increase in comparison with the scales indicated above, the following should be used:
Scale of reduction
1:10n (for example, 1:100; 1:1000, etc.);
1: (2-10 n) (for example, 1: 200; 1: 2000, etc.);
1: (5-10 n) (for example, 1: 500; 1: 5000, etc.);
Scale of increase
(10-n) : 1, for example: 20: 1; 30:1, etc., where n is an integer.
For a visual comparison of the sizes of flat figures depicted at different scales, Drawing 61 shows images of a square (the side of which is 20 mm), made in different scales: 5:1; 2:1; 1:1; 1:2; 1:5. When choosing a scale, you need to take into account the size and complexity of the object being depicted and the size of the selected drawing format. When making a drawing using a reduction (or enlargement) scale, it is recommended to use an “angular scale” instead of calculations (see Drawing 115).

When depicting a part on an enlarged scale it is allowed to draw a simplified life-size image of it on the same sheet (in the upper left corner). The scale 1:1 is indicated above the image. Dimensions are not indicated on such an image (see Drawing 640). If the scale fits into the column with the name provided for it in the corner stamp, then it is designated 1:1; 1:2; 2:1, etc. (Drawings 497 and 523), and in other cases M 1:1; M 1:2; M 2:1, etc. (Drawing 640).
In cases where the image is made on a scale different from that inscribed in the corner stamp, the scale must be indicated under the inscription relating to this image, (View A/M 2:1); (P / M 5:1) see Drawing 641. On tabular, “silent” and similar drawings, scales are not indicated; in this case, a line is drawn in the column of the corner stamp intended to indicate the scale.
The established scales do not apply to drawings obtained by printing or photography.
We note that in the drawings, regardless of the scale on which they are made, only natural (actual) dimensions are indicated and the dimensions of the depicted part are judged from them. Applying reduced or enlarged dimensional numbers obtained from applying reduction or enlargement scales to the drawing is a mistake.

Layout of the drawing.

The layout of the drawing is the placement of images, dimensions and inscriptions on the drawing field (that is, inside the frame).

The layout of the drawing begins by choosing the drawing format in accordance with the overall (i.e., the largest in length and width) dimensions of the future image. For example, if the overall dimensions of the image are 218 X 170, then you need to choose a format that has a slightly larger drawing field, for example, format 11; its drawing margin is equal to the format size minus the margins of the frame and stamp, i.e.
x = 247 x 180.
If the overall dimensions of the image are 360 ​​X 200, then you need to select format 12; its drawing field dimensions are slightly larger than the image dimensions.
It is recommended to place format 11 so that its short side is at the bottom (210 mm), and format 12 and subsequent ones so that its long side is at the bottom (420 mm).
In the case when the image of an object is very simple, and its overall dimensions are large, it is possible to apply a reduction scale without compromising understanding, therefore, the drawing should be executed in a format whose drawing field is slightly larger than the overall dimensions of the reduced image. When depicting an object that is complex in shape, but very small in size, you should apply an enlargement scale, and therefore draw it on a format whose drawing field is slightly larger than the overall dimensions of the enlarged image of the object.

At correct layout in the drawing, the overall cell of the image should be at the same distance from the frame lines on the right and left; above the frame and below the stamp are also at the same distance.
With this arrangement, for images that have vertical and horizontal axes of symmetry, the center O of the drawing field is found (Drawing 62, a), and the image of the object is drawn in such a way that the intersection point of the symmetry axes coincides with the center O of the field (Drawing 62, b).
If there are no prerequisites for depicting an object in a particular position (for example, instructions about the working position of the object, its main view, etc.), then it is recommended to position the image of the object so that its outline is located everywhere at more or less the same distance from frame lines and drawing stamp (i.e. so that the drawing field is more fully used). (Drawing 62, b) shows the correct, and (Drawing 62, c) incorrect (the outline of the image almost touches the side lines of the frame, and above and below there are large, unfilled spaces in the drawing field) layout of the image of the flange outline.
If the image of an object has only one axis of symmetry, for example vertical (Drawing 63, a), then it is combined with a vertical line passing through the center O of the drawing field, then at a distance a2, set upward from the stamp, draw the bottom line of the image of the object and, orienting on these lines, the entire image is constructed; size a 2 = (a - a 1)/2, where a - vertical size drawing margins, and dimension a 1 is vertical overall size images of the object (Drawing 63, b).

If the image of an object is asymmetrical (does not have axes of symmetry, drawing 64, a), then according to the overall dimensions of the object, draw a dimensional cell inside the drawing field, located to the left of the frame at a distance b 2 = (b - b 1)/2 a from below the stamp on distance a 2 = (a - a 1)/2 (drawing 64, b) and an image of an object is drawn inside it.
In the case when it is necessary to draw not one, but two separate images inside the drawing field (Drawing 65, a), first draw two dimensional cells in such a way that
b 2 = (b - b 1)/2;
d 3 = (b - b 1)/2;
a 2 = (a-(a 1 + k + a 1))/2,
where b is the horizontal overall dimension of the drawing field; b 1 is the horizontal overall dimension of the first item, and b 1 is the horizontal overall dimension of the second item; a - vertical overall dimension of the drawing field; a 1 is the vertical overall dimension of the first item, a 1 is the vertical overall dimension of the second item; k is the size of the distance between the dimensional cells (in the vertical direction) (Drawing 65, b); then images of objects are drawn inside the dimensional cells (Drawing 65, c). If the size k between the overall cells does not depend on the number of sizes that need to be placed between the overall cells, then it is taken equal to a 2 ; Then
a 2 =(a - (a 1 + a 1)) / 3
In the case when it is necessary to apply a large number of dimension lines on any side of the image of an object, when arranging the drawing, you should move the dimensional cell to one side or another in such a way that required quantity dimension lines are freely placed between the outline of the image of the object and the lines of the frame (or stamp). An example of such a layout is shown in (Drawing 66, a - c).
If you need to make a drawing based on an existing sketch of an object with dimensional lines applied, then to assemble it you should add the overall size of the object with the dimensions of the distances between the dimensional lines in the vertical and then horizontal directions and, according to the resulting dimensions, draw a general dimensional cell (drawing 67 , A). The further layout of the image is similar to the data previously indicated (B drawing 67, b and c).

The scale of a drawing is the ratio of its linear dimensions to the natural size of the depicted object. This makes it possible to judge the parameters of the object under consideration. It is not always possible to use natural dimensions when drawing up a drawing. There are several reasons for this:

1. Some details are too large sizes to fully display them on paper.
2. Other mechanisms or objects, on the contrary, are not large enough to be displayed. An example is a watch, the internal mechanism of which cannot physically be displayed on paper in real size.

In such cases, images are drawn reduced or enlarged.

Standard scales

The scale of reduction includes:

• 1:2,
• 1:2,5,
• 1:4,
• 1:10,
• 1:15,
• 1:20,
• 1:25,
• 1:50.
• 1:75.

The first number indicates that the image scale is half the size of the object. In the case when the part or mechanism is small, other designations are used: 2:1, 2.5:1, 5:1, 10:1. Also, magnification is made by 20, 40, 50 and 100 times.

How to determine scale

To correctly determine the scale of drawings according to GOST, you need to know the parameters of the part or mechanism. If the object is large, then you can reduce it by dividing by the numbers presented. An example would be doubling the size. If a part, reduced by half, will fit on a sheet of drawing paper, then the scale is 1:2.

Any object that needs to be depicted can be measured using standard methods (using a ruler, for example), and then transferred to paper. The same thing happens when creating something based on a drawing. According to the specified scale, the exact dimensions are determined.

Mainly drawings are used:

• during construction,
• when creating complex mechanisms,
• during the development of parts.

Changing the size allows you to work on designing an object on a small surface of paper, which simplifies the process. If the scale of a certain section of the drawing is different (which happens during construction), then a symbol with the required number is placed next to it.

When creating drawings, many students make mistakes due to lack of experience and knowledge. To avoid this, just order the services of our company. Specialists will quickly complete the work, which will allow you to get a good estimate and see an example of a high-quality drawing. In addition, you can order coursework from us, thesis or an abstract, which will be completed strictly within the agreed time frame.

Why is it necessary to follow GOST

In the document regulating the application of inscriptions, tables, as well as technical requirements, the rules are highlighted, thanks to which the preparation of each drawing occurs in accordance with certain standards. This helps create graphical information that is understandable to any engineer or builder who uses it in their professional activities.

Careful reading of the documents will allow you to correctly present the information and scale of the drawings. GOST 2.302-68*contains the following rules:

• Additional text is only created if presenting graphical information is not practical.
• Everything that is on the drawing must be written in a concise form.
• Each inscription should be displayed parallel to the main one.
• If abbreviations of words are not generally accepted, their presence is unacceptable.
• Only short inscriptions are used around the images, which cannot interfere with the reading of the drawing.
• If the leader line is directed to the surface of the part, then it should end with an arrow, and if it intersects the contour and does not point to a specific place, its end is drawn with a dot.
• If there is a large amount of information that needs to be indicated near the drawing, it is framed.
• If there are tables, they are drawn up in empty space next to the image.
• When using letters to designate drawing elements, they are written in alphabetical order without spaces.

Compliance with all these rules will allow you to create a drawing that meets all requirements and therefore will be convenient for use.

INTRODUCTION

The topographic map is reduced a generalized image of the area showing elements using a system of symbols.
In accordance with the requirements, topographic maps are highly geometric accuracy and geographical relevance. This is ensured by them scale, geodetic basis, cartographic projections and a system of symbols.
The geometric properties of a cartographic image: the size and shape of areas occupied by geographical objects, the distances between individual points, the directions from one to another - are determined by its mathematical basis. Mathematical basis cards includes as components scale, geodetic basis, and map projection.
What a map scale is, what types of scales there are, how to construct a graphic scale and how to use scales will be discussed in the lecture.

6.1. TYPES OF SCALES OF TOPOGRAPHIC MAPS

When drawing up maps and plans, horizontal projections of segments are depicted on paper in a reduced form. The degree of such reduction is characterized by scale.

Map scale (plan) - the ratio of the length of a line on a map (plan) to the length of the horizontal location of the corresponding terrain line

m = l K : d M

Image scale small plots is practically constant throughout the topographic map. At small angles of inclination of the physical surface (on a plain), the length of the horizontal projection of the line differs very little from the length of the inclined line. In these cases, the length scale can be considered the ratio of the length of a line on the map to the length of the corresponding line on the ground.

The scale is indicated on maps in different options

6.1.1. Numerical scale

Numerical scale expressed as a fraction with numerator equal to 1(aliquot fraction).

Or

Denominator M numerical scale shows the degree of reduction in the lengths of lines on a map (plan) in relation to the lengths of the corresponding lines on the ground. Comparing numerical scales with each other, the larger one is the one with the smaller denominator.
Using the numerical scale of the map (plan), you can determine the horizontal location dm lines on the ground

Example.
Map scale 1:50,000. Length of segment on the map lК= 4.0 cm. Determine the horizontal location of the line on the ground.

Solution.
By multiplying the size of the segment on the map in centimeters by the denominator of the numerical scale, we obtain the horizontal distance in centimeters.
d= 4.0 cm × 50,000 = 200,000 cm, or 2,000 m, or 2 km.

Please note that the numerical scale is an abstract quantity that does not have specific units of measurement. If the numerator of a fraction is expressed in centimeters, then the denominator will have the same units of measurement, i.e. centimeters.

For example, a scale of 1:25,000 means that 1 centimeter of map corresponds to 25,000 centimeters of terrain, or 1 inch of map corresponds to 25,000 inches of terrain.

To meet the needs of the economy, science and defense of the country, maps of various scales are needed. For government topographic maps, forest inventory plans, forestry and afforestation plans, standard scales have been determined - scale series(Table 6.1, 6.2).

Scale series of topographic maps

Table 6.1.

Numerical scale	Card name	1cm card corresponds on the ground distance	1 cm2 card corresponds on the area area
	Five thousandth		0.25 hectare
	Ten-thousandth
	Twenty-five thousandth		6.25 hectares
	Fifty thousandth
	One hundred thousandth
	Two hundred thousandth
	Five hundred thousandth
	Millionth

Previously, this series included scales 1: 300,000 and 1: 2,000.

6.1.2. Named scale

Named scale called a verbal expression of a numerical scale. Under the numerical scale on the topographic map there is an inscription explaining how many meters or kilometers on the ground correspond to one centimeter of the map.

For example, on the map under a numerical scale of 1:50,000 it is written: “there are 500 meters in 1 centimeter.” The number 500 in this example is named scale value .
Using a named map scale, you can determine the horizontal distance dm lines on the ground. To do this, you need to multiply the value of the segment, measured on the map in centimeters, by the value of the named scale.

Example. The named scale of the map is “2 kilometers in 1 centimeter”. Length of a segment on the map lК= 6.3 cm. Determine the horizontal location of the line on the ground.
Solution. By multiplying the value of the segment measured on the map in centimeters by the value of the named scale, we obtain the horizontal distance in kilometers on the ground.
d= 6.3 cm × 2 = 12.6 km.

6.1.3. Graphic scales

To avoid mathematical calculations and speed up work on the map, use graphic scales . There are two such scales: linear And transverse .

Linear scale

To construct a linear scale, select an initial segment convenient for a given scale. This original segment ( A) are called basis of scale (Fig. 6.1).

Rice. 6.1. Linear scale. Measured segment on the ground
will CD = ED + CE = 1000 m + 200 m = 1200 m.

The base is laid on a straight line the required number of times, the leftmost base is divided into parts (segment b), which will smallest linear scale divisions . The distance on the ground that corresponds to the smallest division of the linear scale is called linear scale accuracy .

How to use a linear scale:

• place the right leg of the compass on one of the divisions to the right of zero, and the left leg on the left base;
• the length of the line consists of two counts: the count of whole bases and the count of divisions of the left base (Fig. 6.1).
• If a segment on the map is longer than the constructed linear scale, then it is measured in parts.

Transverse scale

For more precise measurements enjoy transverse scale (Fig. 6.2, b).

Figure 6.2. Transverse scale. Measured distance
PK = T.K. + PS + ST = 1 00 +10 + 7 = 117 m.

To construct it, several scale bases are laid out on a straight line segment ( a). Usually the length of the base is 2 cm or 1 cm. At the resulting points, perpendiculars to the line are installed AB and pass through them ten parallel lines at regular intervals. The leftmost base above and below is divided into 10 equal segments and connected by oblique lines. The zero point of the lower base is connected to the first point WITH top base and so on. Get a series of parallel inclined lines, which are called transversals.
The smallest division of the transverse scale is equal to the segment C 1 D 1 , (Fig. 6. 2, A). The adjacent parallel segment differs by this length when moving up the transversal 0C and along a vertical line 0D.
A transverse scale with a base of 2 cm is called normal . If the base of the transverse scale is divided into ten parts, then it is called hundredths . On the hundredth scale, the price of the smallest division is equal to one hundredth of the base.
The transverse scale is engraved on metal rulers, which are called scale rulers.

How to use a transverse scale:

• use a measuring compass to record the length of the line on the map;
• place the right leg of the compass on a whole division of the base, and the left leg on any transversal, while both legs of the compass should be located on a line parallel to the line AB;
• the length of the line consists of three counts: the count of integer bases, plus the count of divisions of the left base, plus the count of divisions up the transversal.

The accuracy of measuring the length of a line using a transverse scale is estimated at half the value of its smallest division.

6.2. VARIETIES OF GRAPHIC SCALES

6.2.1. Transitional scale

Sometimes in practice you have to use a map or aerial photograph, the scale of which is not standard. For example, 1:17,500, i.e. 1 cm on the map corresponds to 175 m on the ground. If you build a linear scale with a base of 2 cm, then the smallest division of the linear scale will be 35 m. Digitization of such a scale causes difficulties in practical work.
To simplify the determination of distances on a topographic map, proceed as follows. The base of the linear scale is not taken as 2 cm, but is calculated so that it corresponds to a round number of meters - 100, 200, etc.

Example. It is required to calculate the length of the base corresponding to 400 m for a map of scale 1:17,500 (175 meters in one centimeter).
To determine what dimensions a 400 m long segment will have on a 1:17,500 scale map, we draw up the proportions:
on the ground on the plan
175 m 1 cm
400 m X cm
X cm = 400 m × 1 cm / 175 m = 2.29 cm.

Having solved the proportion, we conclude: the base of the transition scale in centimeters is equal to the value of the segment on the ground in meters divided by the value of the named scale in meters. The length of the base in our case
A= 400 / 175 = 2.29 cm.

If we now construct a transverse scale with the length of the base A= 2.29 cm, then one division of the left base will correspond to 40 m (Fig. 6.3).

Rice. 6.3. Transitional linear scale.
Measured distance AC = BC + AB = 800 +160 = 960 m.

For more accurate measurements, a transverse transition scale is built on maps and plans.

6.2.2. Steps scale

This scale is used to determine distances measured in steps during visual surveying. The principle of constructing and using the step scale is similar to the transition scale. The base of the step scale is calculated so that it corresponds to the round number of steps (pairs, triplets) - 10, 50, 100, 500.
To calculate the base value of the step scale, it is necessary to determine the shooting scale and calculate the average step length Shsr.
The average step length (pairs of steps) is calculated from the known distance traveled in the forward and reverse directions. By dividing the known distance by the number of steps taken, the average length of one step is obtained. When the earth's surface is tilted, the number of steps taken in the forward and reverse directions will be different. When moving towards higher relief, the step will be shorter, and in reverse side- longer.

Example. A known distance of 100 m is measured in steps. 137 steps were taken in the forward direction, and 139 steps in the reverse direction. Calculate the average length of one step.
Solution. Total distance covered: Σ m = 100 m + 100 m = 200 m. The sum of steps is: Σ w = 137 w + 139 w = 276 w. The average length of one step is:

Shsr= 200 / 276 = 0.72 m.

It is convenient to work with a linear scale, when the scale line is marked every 1 - 3 cm, and the divisions are signed with a round number (10, 20, 50, 100). Obviously, the value of one step of 0.72 m on any scale will have extremely small values. For a scale of 1:2,000, the segment on the plan will be 0.72 / 2,000 = 0.00036 m or 0.036 cm. Ten steps, on the appropriate scale, will be expressed as a segment of 0.36 cm. The most convenient basis for these conditions, in the opinion of author, the value will be 50 steps: 0.036 × 50 = 1.8 cm.
For those who count steps in pairs, a convenient base would be 20 pairs of steps (40 steps) 0.036 × 40 = 1.44 cm.
The length of the base of the step scale can also be calculated from proportions or by the formula
A = (Shsr × KS) / M
Where: Shsr - average value of one step in centimeters,
KS - number of steps at the base of the scale ,
M - scale denominator.

The length of the base for 50 steps on a scale of 1:2000 with the length of one step equal to 72 cm will be:
A= 72 × 50 / 2000 = 1.8 cm.
To construct the step scale for the example above, you need to divide the horizontal line into segments equal to 1.8 cm, and divide the left base into 5 or 10 equal parts.

Rice. 6.4. Step scale.
Measured distance AC = BC + AB = 100 + 20 = 120 sh.

6.3. SCALE ACCURACY

Scale accuracy (maximum scale accuracy) is a horizontal line segment corresponding to 0.1 mm on the plan. The value of 0.1 mm for determining scale accuracy is adopted due to the fact that this is the minimum segment that a person can distinguish with the naked eye.
For example, for a scale of 1:10,000 the scale accuracy will be 1 m. On this scale, 1 cm on the plan corresponds to 10,000 cm (100 m) on the ground, 1 mm - 1,000 cm (10 m), 0.1 mm - 100 cm (1 m). From the above example it follows that If the denominator of the numerical scale is divided by 10,000, we obtain the maximum accuracy of the scale in meters.
For example, for a numerical scale of 1:5,000, the maximum scale accuracy will be 5,000 / 10,000 = 0.5 m.

Scale accuracy allows you to solve two important problems:

• definition minimum sizes objects and terrain objects that are depicted on a given scale, and the sizes of objects that cannot be depicted on a given scale;
• establishing the scale at which the map should be created so that objects and terrain features with predetermined minimum dimensions are depicted on it.

In practice, it is accepted that the length of a segment on a plan or map can be estimated with an accuracy of 0.2 mm. The horizontal distance on the ground, corresponding at a given scale to 0.2 mm (0.02 cm) on the plan, is called graphic scale accuracy . Graphic accuracy in determining distances on a plan or map can only be achieved when using a transverse scale.
It should be borne in mind that when measuring the relative position of contours on a map, the accuracy is determined not by the graphical accuracy, but by the accuracy of the map itself, where errors can average 0.5 mm due to the influence of errors other than graphic ones.
If we take into account the error of the map itself and the measurement error on the map, we can conclude that the graphical accuracy of determining distances on the map is 5 - 7 times worse than the maximum scale accuracy, i.e. it is 0.5 - 0.7 mm on the map scale.

6.4. DETERMINING AN UNKNOWN MAP SCALE

In cases where for some reason there is no scale on the map (for example, it was cut off when gluing), it can be determined in one of the following ways.

• By grid . It is necessary to measure the distance on the map between the grid lines and determine how many kilometers these lines are drawn through; This will determine the scale of the map.

For example, the coordinate lines are designated by the numbers 28, 30, 32, etc. (along the western frame) and 06, 08, 10 (along the southern frame). It is clear that the lines are drawn through 2 km. The distance on the map between adjacent lines is 2 cm. It follows that 2 cm on the map corresponds to 2 km on the ground, and 1 cm on the map corresponds to 1 km on the ground (named scale). This means that the scale of the map will be 1:100,000 (1 centimeter equals 1 kilometer).

• According to the nomenclature of the map sheet. The notation system (nomenclature) of map sheets for each scale is quite definite, therefore, knowing the notation system, it is not difficult to find out the scale of the map.

A map sheet at a scale of 1:1,000,000 (millionths) is designated by one of the letters of the Latin alphabet and one of the numbers from 1 to 60. The designation system for maps of larger scales is based on the nomenclature of sheets of a millionth map and can be represented by the following diagram:

1:1 000 000 - N-37
1:500,000 - N-37-B
1:200,000 - N-37-X
1:100,000 - N-37-117
1:50 000 - N-37-117-A
1:25 000 - N-37-117-A-g

Depending on the location of the map sheet, the letters and numbers that make up its nomenclature will be different, but the order and number of letters and numbers in the nomenclature of a map sheet of a given scale will always be the same.
Thus, if the map has the nomenclature M-35-96, then, by comparing it with the diagram shown, we can immediately say that the scale of this map will be 1:100,000.
For more information on card nomenclature, see Chapter 8.

• By distances between local objects. If there are two objects on the map, the distance between which on the ground is known or can be measured, then to determine the scale you need to divide the number of meters between these objects on the ground by the number of centimeters between the images of these objects on the map. As a result, we get the number of meters in 1 cm of this map (named scale).

For example, it is known that the distance from the settlement. Kuvechino to the lake Glubokoe 5 km. Having measured this distance on the map, we got 4.8 cm. Then
5000 m / 4.8 cm = 1042 m in one centimeter.
Maps at a scale of 1:104,200 are not published, so we round up. After rounding, we will have: 1 cm of the map corresponds to 1,000 m of terrain, i.e., the map scale is 1:100,000.
If there is a road with kilometer posts on the map, then it is most convenient to determine the scale by the distance between them.

• According to the dimensions of the arc length of one minute of the meridian . The frames of topographic maps along meridians and parallels are divided in minutes of arc of the meridian and parallel.

One minute of meridian arc (along the eastern or western frame) corresponds to a distance of 1852 m (nautical mile) on the ground. Knowing this, you can determine the scale of the map in the same way as by the known distance between two terrain objects.
For example, the minute segment along the meridian on the map is 1.8 cm. Therefore, in 1 cm on the map there will be 1852: 1.8 = 1,030 m. By rounding, we get the map scale of 1:100,000.
Our calculations obtained approximate scale values. This happened due to the proximity of the distances taken and the inaccuracy of their measurement on the map.

6.5. TECHNIQUES FOR MEASURING AND POSTPUTING DISTANCES ON A MAP

To measure distances on a map, use a millimeter or scale ruler, a compass-meter, and to measure curved lines, a curvimeter.

6.5.1. Measuring distances with a millimeter ruler

Using a millimeter ruler, measure the distance between given points on the map with an accuracy of 0.1 cm. Multiply the resulting number of centimeters by the value of the named scale. For flat terrain, the result will correspond to the distance on the ground in meters or kilometers.
Example. On a map of scale 1: 50,000 (in 1 cm - 500 m) the distance between two points is 3.4 cm. Determine the distance between these points.
Solution. Named scale: 1 cm 500 m. The distance on the ground between points will be 3.4 × 500 = 1700 m.
At angles of inclination of the earth's surface of more than 10º, it is necessary to introduce an appropriate correction (see below).

6.5.2. Measuring distances with a measuring compass

When measuring a distance in a straight line, the compass needles are placed at the end points, then, without changing the compass opening, the distance is measured using a linear or transverse scale. In the case when the opening of the compass exceeds the length of the linear or transverse scale, the whole number of kilometers is determined by the squares of the coordinate grid, and the remainder is determined in the usual order according to the scale.

Rice. 6.5. Measuring distances with a measuring compass on a linear scale.

To get the length broken line sequentially measure the length of each of its links, and then sum up their values. Such lines are also measured by increasing the compass solution.
Example. To measure the length of a broken line ABCD(Fig. 6.6, A), the legs of the compass are first placed at the points A And IN. Then, rotating the compass around the point IN. move the hind leg from the point A to the point IN", lying on the continuation of the straight line Sun.
Front leg from point IN transferred to point WITH. The result is a compass solution B"C=AB+Sun. By moving the back leg of the compass from the point in the same way IN" to the point WITH", and the front one WITH V D. get a compass solution
C"D = B"C + CD, the length of which is determined using a transverse or linear scale.

Rice. 6.6. Line length measurement: a - broken line ABCD; b - curve A 1 B 1 C 1;
B"C" - auxiliary points

Long curved segments measured along chords by steps of a compass (see Fig. 6.6, b). The pitch of the compass, equal to an integer number of hundreds or tens of meters, is set using a transverse or linear scale. When rearranging the legs of the compass along the measured line in the directions shown in Fig. 6.6, b use arrows to count steps. The total length of the line A 1 C 1 is the sum of the segment A 1 B 1, equal to the step size multiplied by the number of steps, and the remainder B 1 C 1 measured on a transverse or linear scale.

6.5.3. Measuring distances with a curvimeter

Curve segments are measured with a mechanical (Fig. 6.7) or electronic (Fig. 6.8) curvimeter.

Rice. 6.7. Mechanical curvimeter

First, by rotating the wheel by hand, set the arrow to the zero division, then roll the wheel along the measured line. The reading on the dial opposite the end of the hand (in centimeters) is multiplied by the map scale and the distance on the ground is obtained. A digital curvimeter (Fig. 6.7.) is a high-precision, easy-to-use device. The curvimeter includes architectural and engineering functions and has an easy-to-read display. This device can process metric and Anglo-American (feet, inches, etc.) values, allowing you to work with any maps and drawings. You can enter your most frequently used measurement type and the instrument will automatically convert to scale measurements.

Rice. 6.8. Curvimeter digital (electronic)

To increase the accuracy and reliability of the results, it is recommended to carry out all measurements twice - in the forward and reverse directions. In case of minor differences in the measured data, the arithmetic mean of the measured values ​​is taken as the final result.
The accuracy of measuring distances using these methods using a linear scale is 0.5 - 1.0 mm on the map scale. The same, but using a transverse scale is 0.2 - 0.3 mm per 10 cm of line length.

6.5.4. Conversion of horizontal distance to slant range

It should be remembered that as a result of measuring distances on maps, the lengths of horizontal projections of lines (d) are obtained, and not the lengths of lines on the earth's surface (S) (Fig. 6.9).

Rice. 6.9. Slant range ( S) and horizontal distance ( d)

The actual distance on an inclined surface can be calculated using the formula:

where d is the length of the horizontal projection of line S;
v is the angle of inclination of the earth's surface.

The length of a line on a topographic surface can be determined using a table (Table 6.3) of the relative values ​​of corrections to the length of the horizontal distance (in %).

Table 6.3

Tilt angle

Rules for using the table

1. The first line of the table (0 tens) shows the relative values ​​of corrections at tilt angles from 0° to 9°, the second - from 10° to 19°, the third - from 20° to 29°, the fourth - from 30° up to 39°.
2. To determine absolute value amendments, it is necessary:
a) in the table based on the angle of inclination, find the relative value of the correction (if the angle of inclination of the topographic surface is not given by an integer number of degrees, then the relative value of the correction must be found by interpolating between the table values);
b) calculate the absolute value of the correction to the length of the horizontal distance (i.e., multiply this length by the relative value of the correction and divide the resulting product by 100).
3. To determine the length of a line on a topographic surface, the calculated absolute value of the correction must be added to the length of the horizontal alignment.

Example. The topographic map shows the horizontal length to be 1735 m, and the angle of inclination of the topographic surface to be 7°15′. In the table, the relative values ​​of the corrections are given for whole degrees. Therefore, for 7°15" it is necessary to determine the nearest larger and nearest smaller values ​​that are multiples of one degree - 8º and 7º:
for 8° the relative value of the correction is 0.98%;
for 7° 0.75%;
difference in table values ​​of 1º (60′) 0.23%;
the difference between a given angle of inclination of the earth's surface 7°15" and the nearest smaller tabulated value of 7º is 15".
We make up the proportions and find the relative value of the correction for 15":

For 60′ the correction is 0.23%;
For 15′ the correction is x%
x% = = 0.0575 ≈ 0.06%

Relative correction value for inclination angle 7°15"
0,75%+0,06% = 0,81%
Then you need to determine the absolute value of the correction:
= 14.05 m approximately 14 m.
The length of the inclined line on the topographic surface will be:
1735 m + 14 m = 1749 m.

At small angles of inclination (less than 4° - 5°), the difference in the length of the inclined line and its horizontal projection is very small and may not be taken into account.

6.6. MEASUREMENT OF AREA BY MAPS

Determining the areas of plots using topographic maps is based on the geometric relationship between the area of ​​a figure and its linear elements. The scale of the areas is equal to the square of the linear scale.
If the sides of a rectangle on a map are reduced by n times, then the area of ​​this figure will decrease by n 2 times.
For a map of scale 1:10,000 (1 cm 100 m), the scale of the areas will be equal to (1: 10,000) 2 or 1 cm 2 will be 100 m × 100 m = 10,000 m 2 or 1 hectare, and on a map of scale 1 : 1,000,000 per 1 cm 2 - 100 km 2.

To measure areas on maps, graphical, analytical and instrumental methods are used. The use of one or another measurement method is determined by the shape of the area being measured, the specified accuracy of the measurement results, the required speed of obtaining data and the availability of the necessary instruments.

6.6.1. Measuring the area of ​​a plot with straight boundaries

When measuring the area of ​​a plot with straight boundaries, the plot is divided into simple geometric shapes, the area of ​​each of them is measured geometrically and, by summing the areas of individual plots calculated taking into account the map scale, the total area of ​​the object is obtained.

6.6.2. Measuring the area of ​​a plot with a curved contour

Object with curvilinear contour are divided into geometric shapes, having previously straightened the boundaries in such a way that the sum of the cut off sections and the sum of the excesses mutually compensate each other (Fig. 6.10). The measurement results will be, to some extent, approximate.

Rice. 6.10. Straightening the curved boundaries of the site and
breaking down its area into simple geometric shapes

6.6.3. Measuring the area of ​​a site with a complex configuration

Measuring plot areas, having a complex irregular configuration, are often performed using palettes and planimeters, which gives the most accurate results. Grid palette It is a transparent plate with a grid of squares (Fig. 6.11).

Rice. 6.11. Square mesh palette

The palette is placed on the contour being measured and the number of cells and their parts inside the contour is counted. The proportions of incomplete squares are estimated by eye, therefore, to increase the accuracy of measurements, palettes with small squares (with a side of 2 - 5 mm) are used. Before working on this map, determine the area of ​​one cell.
The area of ​​the plot is calculated using the formula:

P = a 2 n,

Where: A - side of the square, expressed in map scale;
n- the number of squares falling within the contour of the measured area

To increase accuracy, the area is determined several times with arbitrary rearrangement of the palette used to any position, including rotation relative to its original position. The arithmetic mean of the measurement results is taken as the final area value.

In addition to mesh palettes, dot and parallel palettes are used, which are transparent plates with engraved dots or lines. The points are placed in one of the corners of the cells of the grid palette with a known division value, then the grid lines are removed (Fig. 6.12).

Rice. 6.12. Spot palette

The weight of each point is equal to the cost of dividing the palette. The area of ​​the measured area is determined by counting the number of points inside the contour and multiplying this number by the weight of the point.
Equally spaced parallel lines are engraved on the parallel palette (Fig. 6.13). The area being measured, when the palette is applied to it, will be divided into a number of trapezoids with the same height h. The parallel line segments inside the contour (midway between the lines) are the midlines of the trapezoid. To determine the area of ​​a plot using this palette, it is necessary to multiply the sum of all measured center lines by the distance between parallel lines of the palette h(taking into account scale).

P = h∑l

Figure 6.13. A palette consisting of a system
parallel lines

Measurement areas of significant plots is carried out using cards using planimeter.

Rice. 6.14. Polar planimeter

The planimeter is used to determine areas mechanically. The polar planimeter is widely used (Fig. 6.14). It consists of two levers - pole and bypass. Determining the contour area with a planimeter comes down to the following steps. Having secured the pole and positioned the needle of the bypass lever at the starting point of the contour, a count is taken. Then the bypass pin is carefully guided along the contour to the starting point and a second reading is taken. The difference in readings will give the area of ​​the contour in divisions of the planimeter. Knowing the absolute value of the planimeter division, the contour area is determined.
The development of technology contributes to the creation of new devices that increase labor productivity when calculating areas, in particular the use modern devices, among which are electronic planimeters.

Rice. 6.15. Electronic planimeter

6.6.4. Calculating the area of ​​a polygon from the coordinates of its vertices
(analytical method)

This method allows you to determine the area of ​​a plot of any configuration, i.e. with any number of vertices whose coordinates (x,y) are known. In this case, the numbering of vertices should be done clockwise.
As can be seen from Fig. 6.16, the area S of the polygon 1-2-3-4 can be considered as the difference between the areas S" of the figure 1y-1-2-3-3y and S" of the figure 1y-1-4-3-3y
S = S" - S".

Rice. 6.16. To calculate the area of ​​a polygon from coordinates.

In turn, each of the areas S" and S" is the sum of the areas of trapezoids, the parallel sides of which are the abscissas of the corresponding vertices of the polygon, and the heights are the differences in the ordinates of the same vertices, i.e.

S " = square 1у-1-2-2у + square 2у-2-3-3у,
S" = pl. 1у-1-4-4у + pl. 4у-4-3-3у
or: 2S " = (x 1 + x 2) (y 2 - y 1) + (x 2 + x 3 ) (y 3 - y 2)
2 S " = (x 1 + x 4) (y 4 - y 1) + (x 4 + x 3) (y 3 - y 4).

Thus,
2S = (x 1 + x 2) (y 2 - y 1) + (x 2 + x 3 ) (y 3 - y 2) - (x 1 + x 4) (y 4 - y 1) - (x 4 + x 3) (y 3 - y 4). Opening the brackets, we get
2S = x 1 y 2 - x 1 y 4 + x 2 y 3 - x 2 y 1 + x 3 y 4 - x 3 y 2 + x 4 y 1 - x 4 y 3

From here
2S = x 1 (y 2 - y 4) + x 2 (y 3 - y 1)+ x 3 (y 4 - y 2) + x 4 (y 1 - y 3) (6.1)
2S = y 1 (x 4 - x 2) + y 2 (x 1 - x 3)+ y 3 (x 2 - x 4)+ y 4 (x 3 - x 1) (6.2)

Let us represent expressions (6.1) and (6.2) in general view, denoting by i serial number(i = 1, 2, ..., n) vertices of the polygon:
(6.3)
(6.4)
Therefore, the doubled area of ​​a polygon is equal to either the sum of the products of each abscissa and the difference between the ordinates of the subsequent and previous vertices of the polygon, or the sum of the products of each ordinate and the difference between the abscissas of the previous and subsequent vertices of the polygon.
Intermediate control of calculations is the satisfaction of the conditions:

0 or = 0
Coordinate values ​​and their differences are usually rounded to tenths of a meter, and products - to whole square meters.
Complex formulas for calculating the area of ​​a plot can be easily solved using Microsoft XL spreadsheets. An example for a polygon (polygon) of 5 points is given in tables 6.4, 6.5.
In Table 6.4 we enter the initial data and formulas.

Table 6.4.

				y i (x i-1 - x i+1)
	Double area in m2			SUM(D2:D6)
	Area in hectares

In Table 6.5 we see the results of the calculations.

Table 6.5.

				y i (x i-1 -x i+1)
	Double area in m2
	Area in hectares

6.7. EYE MEASUREMENTS ON THE MAP

In the practice of cartometric work, eye measurements are widely used, which give approximate results. However, the ability to visually determine distances, directions, areas, slope steepness and other characteristics of objects from a map helps to master the skills of correctly understanding a cartographic image. The accuracy of visual determinations increases with experience. Visual skills prevent gross miscalculations in measurements with instruments.
To determine the length of linear objects on a map, one should visually compare the size of these objects with segments of a kilometer grid or divisions of a linear scale.
To determine the areas of objects, squares of a kilometer grid are used as a kind of palette. Each grid square of maps of scales 1:10,000 - 1:50,000 on the ground corresponds to 1 km 2 (100 hectares), scale 1:100,000 - 4 km 2, 1:200,000 - 16 km 2.
The accuracy of quantitative determinations on the map, with the development of the eye, is 10-15% of the measured value.

Video

Scale problems

Tasks and questions for self-control

1. What elements does the mathematical basis of maps include?
2. Expand the concepts: “scale”, “horizontal distance”, “numerical scale”, “linear scale”, “scale accuracy”, “scale bases”.
3. What is a named map scale and how do I use it?
4. What is a transverse map scale, and what is its purpose?
5. What transverse map scale is considered normal?
6. What scales of topographic maps and forest management tablets are used in Ukraine?
7. What is a transition map scale?
8. How is the transition scale base calculated?
Previous

Machines and some of their parts, buildings and their parts are large, so it is not possible to draw them in full size. Their images have to be drawn in. The smallest details of watches and other mechanisms have to be drawn, on the contrary, on an enlarged scale.

In all cases where possible, details should be drawn in actual size, i.e. on a scale of 1:1.

Reducing or enlarging images any number of times is not permitted. GOST 2.302-68 establishes the following reduction scales: 1:2; 1:2.5; 1:4; 1:5; 1:10; 1:15; 1:20; 1:25; 1:40; 1:50; 1:75; 1:100; 1:200; 1:400; 1:500; 1:800; 1:1000. When drawing up master plans for large objects, it is allowed to use a scale of 1:2000; 1:5000; 1:10,000; 1:20,000; 1:25,000; 1:50,000. Magnification scales are written as a ratio to unity; The standard establishes the following magnification scales: 2:1; 2.5:1; 4:1; 5:1; 10:1; 20:1; 40:1, 50:1; 100:1. IN necessary cases It is allowed to use magnification scales (100l): 1, where n is an integer. In cases where the full word “scale” is not included in the entry, the letter M is placed before the scale designation, for example they write: M 1:2 (reduction scale), M 2:1 (increase scale). In Fig. 1 washer rectangular shape depicted in three scales: life-size (M 1:1), reduced scale and enlarged scale. The linear dimensions of the last image are four times larger than the middle one, and the area occupied by the image is sixteen times larger. Such a sharp change in image size should be taken into account when choosing the scale of the drawing.

TBegin-->TEnd-->

Rice. 1. Comparison of different scales. Linear scales

In addition to numerical scales, linear scales are used in drawing. Linear scales There are two types: simple and transverse (Fig. 1). A simple linear scale, corresponding to a numerical scale of 1: 100, is a line on which, from the zero division, centimeter divisions are laid out to the right, and one of the same divisions, divided into millimeters, to the left. Each centimeter division of the linear scale corresponds to 100 cm (or 1 m). Each millimeter division corresponds, obviously, to one decimeter. Having taken any size from the drawing with a meter, place one needle on the corresponding full division to the right of zero, on -
example for division 3. Then the second needle will show how many decimeters over 3 m the measured size has. In this case it is equal to 3.4 m.

The advantages of a simple linear scale over a regular ruler are as follows:

rn
1. it is always on the drawing;
rn
2. gives more accurate readings, since the dimensions in the drawing are plotted, as a rule, according to a given linear scale;
rn
3. After photographing the drawing, the scale, decreasing proportionally, makes it possible to obtain dimensions without constructing a proportional scale.
rn

More perfect is linear transverse scale. In the drawing it is given for the same scale of 1:100. Oblique lines, transversals, allow you to get not only decimeters, but also centimeters. As an example, the scale shows a size of 3.48 m. Linear scales are used primarily in construction and topographical drawings.

Rice. 2. Scale chart

In design and production practice they often use proportional (angular) scale. It is a simple graph. Suppose you need to construct such a graph for a scale of 1:5. On a horizontal line from point A (Fig. 2) lay a segment equal to 100 mm; at point B, a right angle is constructed and a segment reduced by 5 times (100: 5 = 20 mm) is laid along its second side; connect the resulting point C to point A. The value of 12.8 mm, corresponding to 66 mm, is taken with a measuring compass directly from the graph, without calculating it or using a ruler. The graph is drawn on graph paper or on checkered paper.

For a scale of 1: 2.5, 40 mm are set aside on the continuation of the BC leg, for a scale of 1: 2-50 mm. The series of proportional scales shown in the figure is called a scale graph. Using it allows you to save a significant amount of time. Having constructed a scale graph, use it throughout the entire work on the drawing course.

INTERSTATE STANDARD

UNIFIED SYSTEM OF DESIGN DOCUMENTATION

SCALE

Moscow

INTERSTATE STANDARD

1. This standard establishes the scale of images and their designation on drawings of all industries and construction.

The standard does not apply to drawings obtained by photographing, as well as to illustrations in printed publications, etc.

(Changed edition, Amendment No. 1, No. 2).

2a. In this standard, the following terms with corresponding definitions apply:

scale: The ratio of the linear size of a segment in a drawing to the corresponding linear size of the same segment in real life;

life scale: Scale with ratio 1:1;

zoom scale: A scale with a ratio greater than 1:1 (2:1, etc.);

reduction scale: A scale with a ratio less than 1:1 (1:2, etc.).

(Introduced additionally, Amendment No. 2).

2. The scales of images in the drawings must be selected from the following range:

Scale of reduction	1:2; 1:2,5; 1:4; 1:5; 1:10; 1:15; 1:20; 1:25; 1:40; 1:50; 1:75; 1:100; 1:200; 1:400; 1:500; 1:800; 1:1000
Life size
Scale of increase	2:1; 2,5:1; 4:1; 5:1; 10:1; 20:1; 40:1; 50:1; 100:1

3. When designing master plans for large objects, it is allowed to use a scale of 1:2000; 1:5000; 1:10000; 1:20000; 1:25000; 1:50000.

4. If necessary, it is allowed to use magnification scales (100 n):1, where n- an integer.

5. The scale indicated in the designated column of the title block of the drawing must be indicated as 1:1; 1:2; 2:1, etc.

The scale of a drawing is the ratio of its linear dimensions to the natural size of the depicted object. This makes it possible to judge the parameters of the object under consideration. It is not always possible to use natural dimensions when drawing up a drawing. There are several reasons for this:

1. Some details are too large to be fully displayed on paper.
2. Other mechanisms or objects, on the contrary, are not large enough to be displayed. An example is a watch, the internal mechanism of which cannot physically be displayed on paper in real size.

In such cases, images are drawn reduced or enlarged.

Standard scales

The scale of reduction includes:

• 1:2,5,
• 1:10,
• 1:15,
• 1:20,
• 1:25,
• 1:50.
• 1:75.

The first number indicates that the image scale is half the size of the object. In the case when the part or mechanism is small, other designations are used: 2:1, 2.5:1, 5:1, 10:1. Also, magnification is made by 20, 40, 50 and 100 times.

How to determine scale

To correctly determine the scale of drawings according to GOST, you need to know the parameters of the part or mechanism. If the object is large, then you can reduce it by dividing by the numbers presented. An example would be doubling the size. If a part, reduced by half, will fit on a sheet of drawing paper, then the scale is 1:2.

Any object that needs to be depicted can be measured using standard methods (using a ruler, for example), and then transferred to paper. The same thing happens when creating something based on a drawing. According to the specified scale, the exact dimensions are determined.

Mainly drawings are used:

• during construction,
• when creating complex mechanisms,
• during the development of parts.

Changing the size allows you to work on designing an object on a small surface of paper, which simplifies the process. If the scale of a certain section of the drawing is different (which happens during construction), then a symbol with the required number is placed next to it.

When creating drawings, many students make mistakes due to lack of experience and knowledge. To avoid this, just order the services of our company. Specialists will quickly complete the work, which will allow you to get a good estimate and see an example of a high-quality drawing. In addition, you can order a coursework, dissertation or essay from us, which will be completed strictly within the agreed time frame.

Why is it necessary to follow GOST

The document regulating the application of inscriptions, tables, as well as technical requirements, highlights the rules by which each drawing is drawn up in accordance with certain standards. This helps create graphical information that is understandable to any engineer or builder who uses it in their professional activities.

Careful reading of the documents will allow you to correctly present the information and scale of the drawings. GOST 2.302-68*contains the following rules:

• Additional text is only created if presenting graphical information is not practical.
• Everything that is on the drawing must be written in a concise form.
• Each inscription should be displayed parallel to the main one.
• If abbreviations of words are not generally accepted, their presence is unacceptable.
• Only short inscriptions are used around the images, which cannot interfere with the reading of the drawing.
• If the leader line is directed to the surface of the part, then it should end with an arrow, and if it intersects the contour and does not point to a specific place, its end is drawn with a dot.
• If there is a large amount of information that needs to be indicated near the drawing, it is framed.
• If there are tables, they are drawn up in the empty space next to the image.
• When using letters to designate drawing elements, they are written in alphabetical order without spaces.

Compliance with all these rules will allow you to create a drawing that meets all requirements and therefore will be convenient for use.

This is the relationship between the natural dimensions of an object or object to the linear dimensions of the one depicted in the drawing. The scales of drawings can be expressed in numbers, in which case they are called numerical scales and graphically linear scales.

The numerical scale is indicated by a fraction and shows the factor of reduction and increase in the size of the depicted objects in the drawing. Depending on the purpose of the drawings and also on the complexity of the shapes of the depicted objects and structures in the drawing, the following scales are used when drawing up drawing documents:

Decreases 1:2; 1:2.5; 1:4; 1: 10; 1:15; 1:20; 1:25; 1: 40; 1:50; 1:75; 1: 100; 1:200; 1:400; 1:500; 1:800; 1:1000;

Increases: 2:1; 2.5:1;4:1; 5:1; 10:1; 20:1; 40:1; 50:1; 100:1;

Life-size image 1:1. In the process of designing master plans for large objects, the following scales are used: 1:2000; 1: 5000; 1:10000; 1:20000; 1: 25000; 1:50000 .

If the drawing is made on the same scale, then its value is indicated in the title block of the drawing according to the 1:1 type; 1:2; 1:100 and so on. If any image in the drawing is made in a scale that differs from the indicated scale in the main inscription of the drawing, then in this case indicate a scale of type M 1: 1; M1:2 and so on under the corresponding image name.

When drawing up construction drawings and using a numerical scale, it is necessary to make calculations to determine the size of the line segments that are drawn on the drawing. For example, if the length of the depicted object is 4000 millimeters, and the numerical scale is 1: 50, in order to calculate the length of the segment in the drawing, it is necessary to divide 4000 millimeters by (degree of reduction) 50, and put the resulting value of 80 millimeters on the drawing.

In order to reduce calculations, use a scale bar or construct a linear scale (see Figure 4 a) on a numerical scale of 1:50. At the beginning, draw a straight line in the drawing and mark the base of the scale on it several times. The scale base is a value that is obtained by dividing the unit of measurement adopted in this case (1 m = 1000 mm) by the reduction size 1000:50 = 20 millimeters.

On the left side, the first segment is divided into several equal parts, so that each division corresponds to an integer. If you divide this segment into ten equal parts, then each division will correspond to 0.1 meters, if you divide it into five parts, then 0.2 meters.

In order to use the constructed linear scale, for example, to take the size of 4650 millimeters, you need to place one leg of the measuring compass at four meters, and the other at the sixth and a half fractional division to the left of zero. In cases where the accuracy is insufficient, a transverse scale is used.

Scales of drawings - transverse and angular (proportional)

The transverse scale allows you to determine the size with a certain error. The error can be up to hundredths of the basic unit of measurement. Figure 4b shows an example of determining a size equal to 4.65 m. Hundredths are taken on the vertical segment and tenths on the horizontal.

In the case when an arbitrary scale is used and it is necessary to construct a reduced or enlarged image of an object made according to a given drawing format, an angular scale is used, or as it is also called proportional. The angular scale can be constructed in the form right triangle.

The ratio of the legs of such a right triangle is equal to the multiplicity of the image scale (h: H). If necessary, change the image scale using an angular scale, using only abstract values ​​and without calculating the dimensions of the depicted object. For example, when it is necessary to depict a given drawing on an enlarged scale.

For this we build a right triangle (see Figure 4 c) ABC. In such a triangle, the vertical leg BC is equal to a segment of some straight line, which is taken in a given drawing. Horizontal leg AB equal to length segment on the scale of an enlarged drawing. In order to enlarge the desired segment of a straight line in a given drawing, for example, segment h, you need to lay it parallel to the leg BC of the angular scale (vertically), between the hypotenuse AC and the leg AB.

In this case, the increased size of the desired segment will be equal to the size H taken (horizontally) on the AB side of the angular scale. The angular scale is also used when converting quantities from one numerical scale to another.

Scale is the ratio of the linear dimensions of an image in a drawing to its actual dimensions.

The scale of images and their designation in drawings is established by GOST 2.302-68 (Table 5.3). The scale indicated in the designated column of the title block of the drawing must be indicated as 1:1; 1:2; 1:4; 2:1; 5:1; etc.

Table 5.3 – Drawing scales

When designing master plans for large objects, it is allowed to use a scale of 1:2000; 1:5000; 1:10000; 1:20000; 1:25000; 1:50000.

5.3 Main inscription.

Each sheet is decorated with a frame, the lines of which are spaced from three sides of the format by 5 mm from the left side by 20 mm. The main inscription in accordance with GOST 2.104-68 is placed on the frame line in the lower right corner of the format. On A4 sheets, the main inscription is placed only along the short side. The type and thickness of lines in drawings, diagrams and graphs must comply with GOST 2.303-68. Drawings of the project design documentation are made in pencil. Schemes, graphs, and tables may be made in black ink (paste). All inscriptions on the drawing field, dimensional numbers, and filling in the main inscription are made only in drawing font in accordance with GOST 2.304-81.

Thematic headings are not depicted on the sheets, since the name of the contents of the sheet is indicated in the main inscription. In cases where a sheet with one inscription contains several independent images (poster material), individual images or parts of text are provided with headings.

The main inscription on the first sheets of drawings and diagrams must correspond to Form 1, in text design documents - Form 2 and Form 2a on subsequent sheets. It is allowed to use Form 2a on subsequent sheets of drawings and diagrams.

The corner inscription for drawings and diagrams is located in accordance with Figure 5.1. Filled by rotating the sheet 180 o or 90 o.

Figure 5.1–Location of title block on various drawings

In the columns of the title block, Figures 5.2, 5.3, 5.4, indicate:

– in column 1 – name of the product or its component: name of the graph or diagram, as well as the name of the document, if this document is assigned a code. The name must be short and written in the nominative singular case. If it consists of several words, then a noun is placed in the first place, for example: “Threshing drum”, “Safety clutch”, etc. It is allowed to write in this column the name of the contents of the sheet in the order accepted in the technical literature, for example: “Economic indicators”, “Technological map”, etc.;

– in column 2 – designation of the document (drawing, graphics, diagram, specification, etc.);

– in column 3 – designation of the material (the column is filled in only on drawings of parts). The designation includes the name, brand and standard or specification of the material. If the brand of a material contains its abbreviated name “St”, “SCh”, then the name of this material is not indicated.

Figure 5.2 – Form No. 1

Figure 5.3 – Form No. 2

Figure 5.4 – Form No. 2a

Examples of recording material:

– SCh 25 GOST 1412-85 (gray cast iron, 250 - tensile strength in MPa);

– KCh 30-6 GOST 1215-79 (malleable cast iron, 300 - tensile strength in MPa, 6 - relative elongation in%);

– HF 60 GOST 7293-85 (high-strength cast iron, 600 - tensile strength in MPa);

– St 3 GOST 380-94 (carbon steel of ordinary quality, 3rd steel number);

– Steel 20 GOST 1050-88 (carbon steel, high-quality structural, 20 - carbon content in hundredths of a percent);

– Steel 30 KhNZA GOST 4543-71 (alloy structural steel, 30 - carbon content in hundredths of a percent, chromium no more than 1.5%, nickel 3%, A - high quality);

– Steel U8G GOST 1425-90 (tool carbon steel, 8 - carbon content in tenths of a percent; G - increased manganese content);

– Br04Ts4S17 GOST 613-79 (deformable bronze, O-tin 4%, C-zinc 4%, C-lead 17%);

– BrA9Mts2 GOST 18175-78 (tin-free bronze , processed by pressure, A- aluminum 9%, manganese 2%);

– LTs38Mts2S2 GOST 17711-93 (cast brass, zinc 38%, manganese 2%, lead 2%);

– AL2 GOST 1583-89 (casting aluminum alloy, 2-order alloy number);

– AK4M2TS6 GOST 1583-93 (cast aluminum alloy, silicon 4%, copper 2%, zinc 6%);

– AMts GOST 4784-74 (deformable aluminum alloy, manganese 1.0...1.6%,).

When manufacturing parts from the assortment:

- Square

(from a square profile bar with a square side size of 40 mm according to GOST 2591-88, steel grade 20 according to GOST 1050-88);

– Hexagon

(made of hot-rolled steel with a hexagonal profile in accordance with GOST 2579-88 of normal rolling accuracy, with the size of an inscribed circle - turnkey size - 22 mm, steel grade 25 in accordance with GOST 1050-88);

(hot-rolled round steel of normal rolling accuracy with a diameter of 20 mm in accordance with GOST 2590-88, steel grade St 3 in accordance with GOST 380-94, supplied in accordance with the technical requirements of GOST 535-88);

– Strip

(strip steel 10 mm thick, 70 mm wide according to GOST 103-76, steel grade St 3 according to GOST 380-94, supplied according to the technical requirements of GOST 535-88);

– Corner

(angular equal-flange steel 50x3 mm in size according to GOST 8509-86, steel grade St 3 according to GOST 380-94, standard rolling accuracy B, supplied according to the technical requirements of GOST 535-88);

– I-beam

(hot-rolled I-beam number 30 in accordance with GOST 8239-89 of increased accuracy (B), steel grade St 5 in accordance with GOST 380-94, supplied in accordance with the technical requirements of GOST 535-88);

– Pipe 20x2.8 GOST 3262-75 (ordinary non-galvanized pipe of standard manufacturing precision, unmeasured length, with a nominal bore of 20 mm, wall thickness of 2.8 mm, without thread and without coupling);

– Pipe Ts-R-20x2.8 – 6000 GOST 3262-75 (zinc-coated pipe with increased manufacturing precision, measured length 6000 mm, nominal bore 20 mm, with thread);

(seamless steel pipe of standard manufacturing precision according to GOST 8732-78, with an outer diameter of 70 mm, a wall thickness of 3.5 mm, a length multiple of 1250 mm, steel grade 10, manufactured according to group B of GOST 8731-87);

(steel seamless pipe according to GOST 8732-78 with internal diameter 70 mm, wall thickness 16 mm, of unmeasured length, steel grade 20, category 1, manufactured according to group A, GOST 8731-87);

– Column 4 – letter assigned to this document according to GOST 2.103-68 depending on the nature of the work in the form of a project. The column is filled in from the left cell:

–U – educational document;

–DP – documentation of the diploma project;

–DR – documentation of the thesis;

–KP – documentation of the course project;

–KR – course work documentation;

– Column 5 – product weight (in kg) according to GOST 2.110-95; on drawings of parts and assembly drawings indicate the theoretical or actual mass of the product (in kg) without indicating units of measurement.

It is allowed to indicate the mass in other units of measurement indicating them, for example, 0.25 g, 15 t.

In drawings made on several sheets, the mass is indicated only on the first.

On dimensional and installation drawings, as well as on drawings of parts of prototypes and individual production, it is allowed not to indicate the mass;

– Column 6 – scale (indicated in accordance with GOST 2.302-68).

If the assembly drawing is made on two or more sheets and the images on individual sheets are made on a scale different from that indicated in the title block of the first sheet, column 6 of the title block on these sheets is not filled out;

– Column 7 – serial number of the sheet (on documents consisting of one sheet, the column is not filled in).

Column 8 – the total number of sheets of the document (the column is filled out only on the first sheet).

Column 9 - the name or distinctive index of the enterprise issuing the document (since the department in which the diploma project is being carried out is encrypted in column 2 - designation of the document, in this column it is necessary to enter the name of the institute and the group code). For example: “PGSHA gr. To-51";

– Column 10 – the nature of the work performed by the person signing the document. In the diploma project, the column is filled in starting from the top line with the following abbreviations:

– “Developer”;

– “Consult.”;

- “Hand. etc.";

- “Head. cafe";

- “N.cont.”

– Column 11 – surname of the persons who signed the document;

– Column 12 – signatures of persons whose names are indicated in column 2. Signatures of the persons who developed this document and are responsible for standard control are mandatory;

– Box 13 – date of signing of the document;

When choosing a scale for drawings, we use the following GOST standards:

GOST 2.302-68 Unified system design documentation. Scale.

GOST 21.501-2011 System project documentation for construction. Rules for the execution of working documentation of architectural and structural solutions.

GOST R 21.1101-2013 System of design documentation for construction. Basic requirements for design and working documentation

When developing drawings, the dimensions of graphic images of structures, components, and diagrams, as a rule, do not correspond to real dimensions. The ratio of the size of a graphic image to the size of the depicted object is in a certain ratio, which is usually called scale. To be precise:

Scale is the ratio of the linear dimensions of the image of an object in the drawing to its actual dimensions.

In accordance with GOST R21.1101-2013, construction drawings, as a rule, do not have scales
put down.

In cases where the images on the sheet are made in different scales, the corresponding scale is indicated above each of them.
Architectural and construction drawings of residential and public buildings carried out on the following scales:
floor plans, sections, facades – 1:50; 1:100; 1:200
fragments of plans, sections, facades – 1:50; 1:100
knots – 1:5; 1:10; 1:20
master plan – 1:500; 1:1000

In some cases it is necessary to choose other scales. Let's look at the general list of existing scales.

GOST 2.302 establishes the scale of images for drawings.

Scales can be of the following types:

Natural	Magnification scale	Reduction scale
1:1	1: 2	2:1
	1:2,5	2,5:1
	1:4	4:1
	1:5	5:1
	1:10	10:1
	1:15	20:1
	1:20	40:1
	1:25	50:1
	1:40	100:1
	1:50
	1:75
	1:100
	1:200
	1:400
	1:500
	1:800
	1:1000

When developing drawings, the image scale should be taken as minimal as possible, depending on the complexity of the drawing, but ensuring the clarity of copies made from them.