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]
            ]]
        }
    }'
)