Research On Application Of UAV Tilt Photogrammetry In Quality Inspection Of Topographic Map In Complex Areas

Today,surveying and mapping geospatial information has been integrated with real-world 3D,virtual reality(VR),big data,cloud computing and other new generation information technology,and the surveying and mapping geographic information industry has begun to move towards a stage of rapid development.Under the environment that "real 3D China" has become the key direction of basic surveying and mapping planning,the traditional quality inspection mode of surveying and mapping geographic information products has been difficult to quality inspection work under the new situation.With the rapid development of technologies such as unmanned aerial vehicles,low-altitude remote sensing,and three-dimensional space,new opportunities have been brought about for the upgrading and transformation of surveying and mapping geographic information product quality inspection methods and models.This article takes Langmusi Town in Gannan Tibetan Autonomous Prefecture as the experiment area.For the quality inspection of large-scale topographic maps in an area that is difficult to survey,the traditional methods are difficult to operate,difficult to obtain inspection data,difficult to guarantee inspection coverage,difficult to ensure the safety of operators,and high cost of human resources and low efficiency.The machine tilted photogrammetry method replaces the traditional topographic map quality inspection method,constructs a three-dimensional real-world model of the target area for large-scale topographic map quality inspection,and improves the objectivity,accuracy and comprehensiveness of the quality inspection results.Explore a new method for the quality inspection of large-scale topographic maps in high-altitude and cold areas and even no-man's land.The main research contents and conclusions of the paper are as follows:(1)Optimize the design of tilt photogrammetry in difficult areas for surveying and mapping: Aiming at the problem of oblique photogrammetry aerial photography in an area that is difficult to survey and the difficulty in obtaining high-quality image data,the design of tilt photogrammetry in difficult areas is optimized,including the optimization of image control point layout schemes,and aerial photography.Optimizing the setting of photographing parameters,proposes zoned and layered aerial photography,and adopts techniques such as lowering or flying on the ground according to the specific conditions of the region.(2)Research on inspection data extraction methods based on three-dimensional models:Most areas with difficult surveying and mapping areas have complex distribution of landforms and features,such as cliffs,dense forests,deep valleys and other inaccessible areas,and some areas are difficult to reach due to cultural differences.Temples,private courtyards with high walls,etc.Therefore,the article proposes a method of directly extracting the inspection data from the three-dimensional model of the oblique photography of the sample area to inspect the topographic map to be inspected,which improves the efficiency and accuracy of the quality inspection of the topographic map.(3)Research on the quality inspection method of topographic map using tilt photogrammetry three-dimensional model: discussed the specific steps of large-scale topographic map quality inspection based on drone tilt photogrammetry,and discussed the applicability of this method in the field of topographic map quality inspection It analyzes the accuracy of the test data source,and introduces and utilizes the five aspects of mathematical accuracy,geographic accuracy,data and structure correctness,finishing quality,and accessory quality based on the relevant specifications and discriminant indicators for quality inspection of large-scale topographic maps.Oblique photogrammetry builds the specific theory and method of large-scale topographic map quality inspection of 3D model,and improves the defect deduction method model of traditional topographic map quality evaluation based on inspection data extracted from 3D model.(4)Reliability analysis of topographic map inspection results based on the real three-dimensional model of oblique photogrammetry: Langmusi Town,Gannan Prefecture,Gansu Province was used as the experimental area to test the 1:1000 large-scale topographic map of the experimental area of Langmusi Town.And described the data processing process and results of this experiment.Analyze the specific experimental data of five quality elements including mathematical accuracy,and demonstrate the feasibility of applying the new method to the quality inspection of large-scale topographic maps.The reliability of the new method is confirmed by comparison with the results of traditional quality inspection methods.The research results show that the topographic map inspection method based on the high-precision oblique real-view 3D model can meet the quality inspection requirements of topographic maps.Compared with traditional inspection methods,it optimizes the method of acquiring inspection data and effectively breaks through the limitations of topographic map quality inspection in an area that is difficult to survey.Improve inspection efficiency and reliability.