ST_Boundary

ST_Boundary takes a geometry column and returns a geometry column. The output column contains the topological boundary of the given geometry. The function will return a linestring if the input is a polygon and a multipoint if the input is a linestring. Point and multipoint inputs are not supported.

Function	Syntax
Python	`boundary(geometry)`
SQL	`ST_Boundary(geometry)`

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

This function implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

Examples

Python

SQL

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from geoanalytics.sql import functions as ST

data = [
    ("POINT (10, 30)",),
    ("MULTIPOINT (0 0, 10 10, 20 20)", ),
    ("LINESTRING (0 0, 10 10, 20 20)", ),
    ("POLYGON ((0 0, 5 5, 10 0, 20 10))", )
]

df = spark.createDataFrame(data, ["wkt"])\
          .select(ST.geom_from_text("wkt").alias("geometry"))

df.select(ST.boundary("geometry").alias("boundary")).show(truncate=False)

Result
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+----------------------------------------------+
|boundary                                      |
+----------------------------------------------+
|NULL                                          |
|NULL                                          |
|{"points":[[0,0],[20,20]]}                    |
|{"paths":[[[0,0],[20,10],[10,0],[5,5],[0,0]]]}|
+----------------------------------------------+

Version table

Release	Notes
1.0.0	Function introduced

ST_Boundary

Examples

Version table

Related topics