polygonize-kml-groundoverlay

Makefile workflow: takes in a folder of KML files with flat GroundOverlay images, extracts clean vector polygons from them

Useful for output from radio reach tools like RadioMobile, Nautel, SPLAT or CloudRF which generate this kind of KML.

Input (screenshot of layer from Google Earth)

output (GeoJSON polgons)

Prerequisites

• Docker
• Mapshaper (npm install -g mapshaper)

Instructions

Use make to generate the summary geojson file from all kml files in the data\kml\ folder. Add mapshaper rules to merge in other data.

Credits

• Makes use of geodata/grass and kartoza/qgis-desktop Docker images for GRASS and GDAL libraries.
• Also makes use of WorldFileTool.jar, more details.
• Thanks to Farm Radio International support to explore the toolchain.

GRASS is needed to clean the polygons so they can be union'd or intersected.