ST_ShortestLine

ST_ShortestLine takes two geometry columns and returns a linestring column. The output column contains the shortest line that touches two geometries, using planar distance calculation. This function returns only one shortest line if there are more than one. If the two input geometries intersect, an empty line geometry is returned. If the two geometry columns are in different spatial references, the function automatically transforms the second geometry into the spatial reference of the first.

If your input geometries are in a geographic coordinate system, consider using ST_GeodesicShortestLine to identify the shortest line.

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

Examples

1
2
3
4
5
6
7
8
9
10
11
from geoanalytics.sql import functions as ST

line_text = 'LINESTRING (30 10, 30 40)'

df = spark.createDataFrame([(line_text, 20, 25)], ["wkt", "lon", "lat"]) \
          .withColumn("line", ST.line_from_text("wkt")) \
          .withColumn("point", ST.point("lon", "lat"))

df.select(ST.shortest_line("line", "point").alias("shortest_line")).show(truncate = False)

1
2
3
4
5
+-----------------------------+
|shortest_line                |
+-----------------------------+
|{"paths":[[[30,25],[20,25]]]}|
+-----------------------------+

Version table

Related topics

• SQL functions
• ST_GeodesicShortestLine
• Coordinate systems and transformations