People see the faces reflect the face of the earth's surface morphology and the topographic map is a complicated matter. Whether changes in topography of the mountain, or river water network HUTANG plain water-intensive, the map features a variety of features and symbols are an accurate reflection of the actual situation on the ground. They are mapping out how to do?
         This is the first clearly defined topographic maps for each point on the needs of three basic elements: direction, distance and elevation. At the same time, the three basic elements must also have the initial direction and elevation coordinates of the starting point for the basis of zero.
         Fixed on the map with a white board mapping topographic maps, the first thing I have orientation on the drawing board, which can be measured in accordance with prior land control points as the initial orientation direction; Mapping in the summary, he can refer to North needle orientation. Drawing board after orientation, it is necessary to determine the point in mapping the location of drawings for the national reunification of the basic topographic map of the mapping, is a standardized point of the requirements of the coordinates outreach; but in some areas for small area mapping, can be assumed independent The plane Cartesian coordinate system origin, you can start by measuring the two elements of direction and distance of approach any other determination of the ground point coordinates of the location of the plane. As regards the point of elevation, elevation as a result of the national system has been laid throughout the country a lot of elevation based on a unified standard of points available, the general standard of measurement could be detected even mapping zone mapping is therefore used in trigonometric leveling horizon At the same time, the method can be determined at any point and the elevation of the point.
         We know that the ground topography and features of any description are available by the transformation point of the lines is reflected in the composition. Topography can be reflected in its high and low contour and shape change; features such as housing, roads, rivers, etc. can be used by its conversion feature points of the lines that constitute them; there are many special features of the landscape and there are special symbols legend to express. Therefore, the work of surveying and mapping topographic maps and is in fact determined that the ground topography and features all the feature points. Of course, different scales of topographic maps, but also still have the choice of feature points and the integrated character issues.
         With the mapping of science and technology development and progress, the modern topographic map of a large number of arduous work by mapping the field of traditional white shift mapping indoor aerial photography mapping and space remote sensing mapping, and has been gradually moving towards all-digital, automated test Fig.