geoDifference
Returns a new polygon with the difference of the second polygon clipped from the first polygon.
Syntax
geoDifference(polygon1, polygon2)
Parameters
Parameter | Description |
polygon1 | Required. Polygon or MultiPolygon GeoJSON feature. |
polygon2 | Required. Polygon or MultiPolygon GeoJSON feature to remove from polygon1. |
Example
Return a GeoJSON Polygon that removes City Park (polygon2) from Colorado (polygon1).
SELECT geoDifference('{ "type": "Feature", "properties": { "name":"Colorado" }, "geometry": { "type": "Polygon", "coordinates": [[ [-109.072265625,37.00255267215955], [-102.01904296874999,37.00255267215955], [-102.01904296874999,41.0130657870063], [-109.072265625,41.0130657870063], [-109.072265625,37.00255267215955] ]] } }', '{ "type": "Feature", "properties": { "name":"City Park" }, "geometry": { "type": "Polygon", "coordinates": [[ [-104.95973110198975,39.7543828214657], [-104.95955944061278,39.744781185675386], [-104.95904445648193,39.74422022399989], [-104.95835781097412,39.74402223643582], [-104.94097709655762,39.74392324244047], [-104.9408483505249,39.75434982844515], [-104.95973110198975,39.7543828214657] ]] } }' )