Documentation

geoDifference

Returns a new polygon with the difference of the second polygon clipped from the first polygon.

Syntax

geoDifference(polygon1, polygon2)

Parameters

ParameterDescription
polygon1Required. Polygon or MultiPolygon GeoJSON feature.
polygon2Required. 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]
      ]]
    }
  }'
)