Agisoft Metashape photo elevation correction with python source code
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foreword
Agisoft Metashape can directly read the latitude, longitude and elevation information in the photos. The photos obtained by the drone are stored in WGS84 latitude and longitude coordinates and geodetic heights, while the national 2000 Gauss projection coordinates and 85 elevations are used in our actual measurement. You can convert WGS84 latitude and longitude coordinates to projected coordinates through my previous blog post (Metashape coordinate system selection coordinate conversion). This article explains how to use python scripts to realize the conversion of earth heights to 85 elevations (small area areas) through elevation correction numbers. Large areas can be passed through seven parameters. The way to realize the transformation of geodetic height to 85 elevation, so as to realize the conversion of the WGS84 latitude and longitude coordinates and geodetic height of the photo to the projected coordinates of the ground survey coordinate system and the 85 elevation are consistent with the control point coordinate system and elevation, which is convenient for later puncture points. It is necessary to improve the accuracy of results.
1. Calculate the elevation correction number
The corresponding elevation correction number can be obtained by measuring the original geodetic height of the image control point and the converted 85 elevation. In plain areas with a small area (less than 10 square kilometers), the elevation difference (elevation anomaly) is generally Not big, aerial survey topographic map items can be added and subtracted