Export and Application of Red Lines in Surveying and Mapping Tasks

（1） Establishment of drone mapping red line – only knowing the construction boundary points
In many cases, Party A can only provide boundary points around the survey area to surveyors, and determining the red line range is quite complex and cannot be completed overnight. The following is a case tutorial on how to use construction boundary points to determine the red line range.

1. Obtain the boundary points of the customer’s testing area, which will be indicated on relevant billboards and documents
2. Organize the boundary points, arrange them in an Excel spreadsheet, save them as CSV files, and modify them to DAT files with suffixes
3. Open CAD and select data, import the dat file into CASS1 for point expansion, and use lines (command: PL) to draw a closed area.
4. To set the relevant projections and central meridian, click on File – CASS Parameter Configuration – Projection Conversion Parameters to configure the specific parameters.
5. After setting up, select the range line we need to export, and then check the database – Export to Google Earth format.
6. Finally, import the exported KML into map software, draw the KML region, and export it for use during flight.
   （2） Establishment of drone surveying red line – with CAD base map
   If Party A can provide a CAD base map, multiple parts can be omitted, and only the projection and central meridian need to be adjusted. Finally, export the KML to the map software to draw the area KML.
7. Set the relevant projections and central meridian on the CAD base map, click on File – CASS Parameter Configuration – Projection Conversion Parameters, and set the specific parameters.
8. After setting up, select the range line we need to export, and then check the database – Export to Google Earth format.
9. Finally, import the exported KML into map software, draw the KML region, and export it for use during flight.