The Aerial Photogrammetry For The City Planning Revision Of Changsha

The paper study making1:10000digital orthophoto map and updating1:10000topographic map of Changsha planning area, using aerial photogrammetry approach, because the current situation that basic surveying and mapping information of Changsha City is not strong enough modern and large, and is unable to meet a new city planning revision working. The "on-demand mapping" concept is put forward to meet the process of general planning revision work. Only the area that has important targets of planning work is aerial mapping. So its product has both meet the content and precision of planning need, but also the period of mapping is shortened. For aerial triangulation, directional data that1:10000mapping required is completed to obtained, using space positioning and inertial navigation systems onboard aerial photography instrument, and existed the control survey data. So the field survey is not need to conducted. Digital elevation model can be extracted from terrain map, encryption and characteristics, only isolated instances is need to corrected through the stereoscopic observation. The true, beautiful orthophoto map outcome is quickly get using the following method. First of all,the digital differential rectification of single-image has been made. And then, the color infrared aerial images which vegetation features is enhanced in spectral reflection characteristic, and the true color aerial photo is fused by replacement of the fusion band. Then, the color of image is regional uniformed by using Photoshop software adjust the gray histogram, color curve method and so on. Because a variety of color of surface features is caused by the different features, brightness and saturation, shooting angle and light and many other reasons. At last the image is fine processed. The1:10000topographic map is updated by the following method.First the surface features is collected and the projection difference is revised in the orthophoto map. Then the note information of the other features is extracted from the existing data. At last, the contour is generated automatically from the DEM without stereoscopic observation, field measurement and the annotation. According to the city overall planning implementation and the rapid development of the city planning and construction, the indicators of the current city builds situation is reflected clearly and the planning process is ensure largely by the surveying and mapping results that is get by Multi-angle and crossover operation. Mapping worker can save working time, cost and labor intensity greatly through the mode of operation of on-demand mapping.