DXF format. Use MAPGIS to generate contour lines, and export the format to the DXF format of MAPGIS. Use the file function to convert the saved DXF format files into MAPGIS WL and WT files, and they can be edited. After years of painstaking research and development, 91 Satellite Assistant software has formed a mature geographical information system solution and product system, and has a number of completely independent intellectual property rights and patents.