0017 Polygons are GeoJSON files in longitude / latitude or radar grid coordinates¶

Status¶

Accepted

Date¶

2026-09-29

Context¶

Users draw polygons on results to keep or remove areas (e.g. water, layover, an area of interest). The polygons must be saved, reused for other results of the same scene and exchanged with GIS software. Results are on the radar grid or have longitude / latitude (and web mercator coordinates for map views).

Decision¶

Polygons are GeoJSON FeatureCollections of Polygon features (moraine.polygon), as specified in docs/contracts/data.md.
Vertices are longitude / latitude (standard GeoJSON), or range / azimuth pixel coordinates marked by the top level member moraine_coordinates = "radar_grid". moraine.cli.view saves radar grid polygons for radar grid pyramids and longitude / latitude for web mercator pyramids.
polygon-mask turns them into a bool mask (True to keep) of a raster or point cloud, keeping the inside or the outside; applying the mask is left to existing commands (math, pc-logic-pc).

Consequences¶

Longitude / latitude polygons open in QGIS and other GIS software and apply to any result with longitude / latitude (load-gamma-lat-lon-hgt, point clouds made with ras2pc).
Radar grid polygons apply to every raster and point cloud of the same radar geometry.

Do not¶

Do not store polygons in web mercator or other projected coordinates.
Do not write masking into each processing command; make a mask and combine it.