What are the methods of topographic mapping?

What are the methods of topographic mapping? Topographic map is an indispensable tool for us to know the topography at ordinary times. Although topographic map looks simple, there are many methods and skills in the actual surveying and mapping process. In the past, when technology was underdeveloped, topographic map needed pure manual surveying and mapping, which was very troublesome, but now there are many ways. What are the methods for topographic map surveying and mapping? Come and have a look with us!

What are the methods of topographic mapping?

They can be divided into theodolite mapping, large flat-panel mapping, small flat-panel mapping combined with theodolite mapping, photogrammetry and so on. Among them, photogrammetry is generally used for surveying and mapping small and medium-scale topographic maps, while other methods are mainly used for surveying and mapping large-scale topographic maps. This topic mainly introduces this kind of method. The water system should draw bridges and sluices first, then draw double-line rivers, lakes, canals, coastlines and single-line rivers, and then draw embankments, steep banks, beaches and ferries. When the river meets the bridge, it should be interrupted; When a single-line ditch intersects a double-line river, the waterline should be disconnected and bent at one point; When two two-lane rivers intersect, they should be connected with each other.

Basic methods of topographic mapping

Before topographic mapping, complicated topographic survey is needed, and then the map is drawn by scientific methods according to the data obtained from topographic survey. Generally, a topographic map has three elements, including orientation, distance and elevation. Before drawing a topographic map, the direction should be determined first. Generally, a topographic map is drawn in the traditional direction of upper north and lower south. After determining the direction, the coordinate origin and elevation zero point should be determined as reference points on the topographic map. After finishing these, mark the features obtained by topographic survey on the topographic map, express them with various symbols, and draw them with contour lines according to the shape and height of each feature.

How to use topographic map

1. Every project construction is inseparable from topographic map, so you must be familiar with the following issues: framing, numbering and outline of topographic map; Coordinate system of topographic map; Height system; Scale and orientation of topographic map; Topographic map schema; Contours, etc.

2. For map users, only by mastering the method of evaluating the accuracy of topographic maps can they correctly select the topographic maps that meet the requirements. When choosing topographic map, we should not only consider the accuracy of points and elevations, but also consider the designed objects and other factors.

3. The basic contents of topographic map application are: determining the coordinates, side length and azimuth of design points on the map; To find the elevation of any point on the map; Find the slope of the vegetable straight line on the map; Select the shortest route on the map according to the restricted slope; Draw a section in the known direction on the topographic map.

4. The application of topographic map in engineering planning and design is: drainage and irrigation engineering planning; Calculate catchment area and reservoir capacity on topographic map; Determine the toe line of dam slope on the map; Level the field, etc.

The above is an introduction to the methods of topographic mapping, which I hope will help you.