ST_IsSimple

ST_IsSimple takes a geometry column and returns a boolean column. The output returns True if the given geometry is simple; otherwise, it returns False. The criteria for simplicity vary for each geometry type and are as follows:

• A point is always simple.
• A multipoint is considered simple if no two points are coincident.
• A linestring is considered simple if it does not cross the same point twice, except for start and end points. A multipart linestring is only considered simple if the parts do not interect except at the start or end points of the parts.
• A polygon or multipart polygon is considered simple if each ring does not cross the same point twice and no two rings cross or intersect except at a single point (i.e. they are tangent at a point but not a line).

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

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, Linestring

data = [
    (Linestring([[[5,5],[7,6],[6,6],[6,8]]]), ),
    (Linestring([[[5,5],[7,6],[6,6],[5,5]]]), ),
    (Linestring([[[5,5],[7,6],[6,6],[6,6],[5,5]]]), )
]

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

df.select(ST.is_simple("linestring").alias("is_simple")).show()

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+---------+
|is_simple|
+---------+
|     true|
|     true|
|    false|
+---------+

Version table

Related topics

• SQL functions
• Data sources
• Coordinate systems and transformations