ST_Difference

ST_Difference takes two geometry columns and returns a geometry column. The result geometries represent the parts of the first geometry that do not intersect the second geometry. The result column geometry type will be that of the first geometry. If the first geometry is completely contained in the second geometry, then null geometry is returned.

If the two geometry columns are in different spatial references, the function will automatically transform the second geometry into the spatial reference of the first.

For more details, go to the GeoAnalytics Engine API reference for difference.

This function implements the OpenGIS Simple Features Implementation Specification for SQL 1.2.1.

Examples

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from geoanalytics.sql import functions as ST, MultiPoint

data = [
    (MultiPoint([[30,10],[10,30],[20,0]]), MultiPoint([[30,10],[10,30]]))
]

df = spark.createDataFrame(data, ["mpoint1", "mpoint2"])

df.select(ST.difference("mpoint1", "mpoint2").alias("difference")).show()

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+-------------------+
|         difference|
+-------------------+
|{"points":[[20,0]]}|
+-------------------+

Version table

Related topics

• SQL functions
• ST_SymDifference
• Data sources
• Coordinate systems and transformations