A Quick Rectify Method for Road Distortion in Orthophoto Production in the Third Land Survey

It is the basis for resource and environmental monitoring and census of national conditions when orthophoto is produced as the base map in land survey. Aiming at the large number of distorted areas existing in the orthorectified image, especially the road area, this paper proposes a new method. That is to say, Real-time local orthorectification is carried out by editing DEM in the road distortion area. It shows that the method achieves a rapid rectify of the image road distortion area, There is no obvious misalignment of the road edge area after rectifying the high-resolution satellite imagery of the GF-2 and TRIPLESAT-2 experimental data. In addition, through comparing the accuracy of a certain number control points in the road area, before and after local orthorectification, it also shows that the method significantly improves the accuracy of the road distortion area, whose planar accuracy is better than 4 m. and meeting the requirements of Orthophoto production accuracy of 1∶10 000.