ST_Cast

ST_Cast takes a geometry column and a string and returns a geometry column. The result column contains the input geometries cast to the geometry type specified by the string value. The string value can be 'point', 'multipoint', 'linestring', 'polygon', or 'geometry'. The function will return null when the input geometries cannot be cast to the specified type.

This function is commonly used to:

• Cast from a specific geometry type to the generic geometry type when merging two geometry columns with different types.
• Cast from the generic geometry type to a specific geometry type when using a function or tool that requires a specific geometry type as input.

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

Examples

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from geoanalytics.sql import functions as ST, Point

df = spark.createDataFrame([(Point(10, 10),)], ["point"])

df.printSchema()

df.select(ST.cast("point", "geometry").alias("point")).printSchema()

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root
 |-- point: point (nullable = true)

root
 |-- point: geometry (nullable = true)

Version table

Related topics

• SQL functions
• Data sources
• Coordinate systems and transformations