Traditional Culture Encyclopedia - Photography major - How to measure the horizontal distance of contour lines
How to measure the horizontal distance of contour lines
The steeper the slope, the smaller the horizontal distance of contour lines.
Question 2: How to choose the scale for line survey ⑤ Surveying and mapping the line section and cross section according to the engineering needs. The scale is determined according to the actual requirements of the project. All landowners ... three. Basic process of line survey (1) Planning and route selection stage is the beginning stage of line engineering. ...
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Microsoft? Windows? XP or Microsoft? Windows? 2000 (with Service Pack 3 or later). If you are not sure whether your operating system is up to date, please go to Microsoft. Windows? Update the website.
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Question 4: The difference between the horizontal distance of contour lines and the horizontal distance of elevation points,
Question 5: What is the slope of the terrain with a large horizontal distance on the same map? On the topographic map, the horizontal distance between two adjacent contour lines is the horizontal distance of contour lines.
On the same map, where the horizontal distance is large, the height difference is small and the terrain slope is slow. Where the horizontal distance is small, the height difference is large and the terrain slope is steep.
Question 6: What is slope? How to determine the slope between two points on the topographic map is the ratio of height difference to horizontal distance, that is, i=h/D× 100%. For the slope between two points on the map, the elevation of the two points can be calculated first, and their height difference H can be obtained by subtraction. Then use a ruler to measure the length of two points on the map and multiply it by the denominator of the topographic map scale, and you can get the actual horizontal distance d between two points on the ground, so their slope I = h/d× 100%.
Question 7: What is the main use of large-scale topographic survey in mountainous areas? A. 1. 1 topographic map and its scale selectively represent various natural and social elements of the earth's surface on a plane according to certain mathematical rules, commonly known as maps. Maps can be divided into general maps and thematic maps. Ordinary map is a map that comprehensively reflects the general characteristics of objects and phenomena on the ground, including various natural geographical elements (such as water system, landform, vegetation, etc.). ) and social factors (such as residential areas, administrative divisions, traffic routes), but do not highlight one of them; Thematic maps are maps that emphasize one or more elements of natural and social phenomena, such as traffic maps and water system maps. Topographic map is an orthographic projection map that represents the plane position and elevation of ground objects and landforms with specified symbols according to a certain proportion. Topographic map is a kind of ordinary map. A map that only shows the shape and plane position of ground objects, but not the ups and downs of the ground, is called a plan. The ratio of the length d of a straight line on the map to the actual length d of the corresponding straight line on the ground is called the scale of topographic map. The scale of topographic map can be divided into digital scale and graphic scale. 1. The digital scale is defined as (A- 1). Usually, the digital scale is represented by the numerator of 1 and the denominator of a relatively large integer m. The larger m is, the smaller the scale value is. The smaller m is, the larger the scale value is. For example, 1:500 is greater than 1: 1000. Generally speaking, topographic maps with scales of 1:500, 1: 1000, 1:2000, 1:5000 are called large-scale topographic maps, which are called1:kloc. Topographic maps with scales of1:250,000,1:500,000,1:kloc-0/10,000 are called small-scale topographic maps. The regulations in China are 1: 1 10,000,1:25,000,1:50,000,1:/10,000,1:250,000,/kloc-0. Large-scale topographic maps are generally needed for urban and engineering construction, among which 1: 500 and 1: 1000 topographic maps are generally measured by flatbed, theodolite or total station. The topographic maps of 1: 2000 and 1: 5000 are generally drawn by scaling down the topographic maps of 1: 1000. Large-area topographic map of 1: 500 ~ 1: 5000 can also be drawn by aerial photogrammetry. Figure A- 1 Table of Digital Scale and Graphic Scale on Topographic Map A- 1 Selection of Topographic Map Scale Accuracy (m) Usage1:100001.0 Urban Master Planning, Site Selection, Regional Layout and Scheme Comparison/KLOC-0 Detailed urban planning and preliminary design of engineering projects in February 2000 654338Figures graphic scale is drawn below the digital scale, which is used to directly take the horizontal distance of straight lines on the map with subdivisions, and at the same time, it can offset the influence of drawing expansion and deformation when measuring the length on the map. 3. Accuracy of scale Because the minimum distance that human eyes can distinguish on the map is 0. 1mm, if the scale of topographic map is 1: m, then the field horizontal distance represented by 0. 1mm on the map is called the accuracy of scale. According to the accuracy of scale, the ranging accuracy of topographic map can be determined. For example, when surveying and mapping a topographic map with the scale of 1: 1000, the scale accuracy is 0. 1m, then the accuracy of the distance only needs 0. 1m, because the distance less than the field 0. 1m cannot be represented on the map. For another example, when the shortest length of the site required to output energy on the design drawing is 0.05m, the scale adopted shall not be less than 0.1mm/0.05 m =1:500. The larger the scale, the more detailed and accurate the representation of features and landforms, but the higher the workload and cost of surveying and mapping. Table A- 1 lists the scale accuracy of several scale topographic maps, and indicates that they can be used according to their purposes ...
Question 8: How did you do it? 1. Features: refers to all kinds of tangible things (such as mountains, rivers, forests, buildings, etc.). ) and intangible things (such as provincial and county boundaries, etc.). ) On the ground. Generally refers to a relatively fixed object on the earth's surface.
Geomorphology is the general name of various forms of the earth's surface, also known as geomorphology.
Topography: Geomorphology (body) refers to various local spatial entities on the surface of the earth (or other planets), and can also be called relatively independent surface undulating units, such as mountains, hills, plateaus and basins.
Topographic map: it is a map characterized by large-scale and quantitative expression of topography, mainly referring to the projection map of the undulating shape of the surface and the position and shape of ground objects on the horizontal plane.
Scale of topographic map: the ratio of the length of a line segment on the map to the horizontal distance d of the corresponding line segment on the ground.
Scale accuracy: The field horizontal distance represented by 0. 1mm on topographic map is called scale accuracy.
2. There are four kinds of ground object symbols: proportional symbols, non-proportional symbols and semi-proportional symbols.
3. Contour: refers to the closed curve connected by points with equal elevation on the topographic map.
The first curve: also called basic contour line, is a contour line drawn according to the basic vertical interval.
Curve counting: For the convenience of reading, draw a contour line in bold every four contours from the starting point. This bold contour line is the curve counting (also called bold contour line).
Interpolation curve: In a flat area, if you draw a topographic map with basic intervals, there are often few contour lines in a map, which cannot express the actual topographic situation. Therefore, in order to show the local geomorphological features in a picture, the vertical interval, that is, half of the basic vertical interval, is used to draw contour lines, which are called inter-curves.
Vertical spacing: the height difference between two adjacent contour lines on topographic map (also called relative height: it must be on the same contour line).
Horizontal distance of contour lines: On the topographic map, the horizontal distance between two adjacent contour lines is the horizontal distance of contour lines.
Slope: it is the steepness of the surface unit, and the ratio of the vertical height h to the horizontal distance l of the slope is usually called slope.
4. Direct measurement: direct measurement.
The coordinate inversion algorithm is calculated according to the coordinate inversion formula in measurement.
Known a and b coordinates; △X/AB=Xb-Xa, △Y/AB=Yb-Ya, R/AB = aretan△Y/AB÷X/AB△Y/AB, △X/AB, the absolute value direct measurement method is suitable for direct measurement, and the line segment is short and small, or the accuracy requirement is low, while the coordinate inverse algorithm is suitable.
5. Transparent grid paper method, parallel line method and analytical method.
Question 9: Read "Contour Topographic Map" and complete the following questions (10) (1). According to the scale, the actual horizontal distance between CDs is kilometers ((1)1.6 (2) b (3) The contour lines of CD lines are sparse, and the slope is gentle. (4) The cliff is steep. According to "distance on map ÷ scale = actual distance", it can be calculated by substituting the numerical value, that is, 2 ÷1/80000 =160000 (cm) =1.6 (km). (2) According to the map analysis, the vertical interval of this contour topographic map is judged because the contour line is sparse and the slope is gentle. (4) On the contour topographic map, the overlapping part of several contours with different altitudes is a steep cliff. As can be seen from the map, A is steep and suitable for rock climbing.
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