ST_GeodesicDensify takes a geometry column and a numeric max_segment_length value and returns a geometry column. This
function adds vertices along linestrings or polygons to create densified approximations of geodesic segments with each
segment being no longer than max. The max_segment_length should be specified in meters and greater
than zero. This function is more accurate but less performant than ST_Densify
and requires that a spatial reference is set on the input geometry column. To learn more about the difference between
planar and geodesic calculations, see Coordinate systems and transformations.
| Function | Syntax |
|---|---|
| Python | geodesic |
| SQL | ST |
| Scala | geodesic |
For more details, go to the GeoAnalytics Engine API reference for geodesic_densify.
Examples
from geoanalytics.sql import functions as ST
LINE_WKT = 'LINESTRING (117.61983168124925 34.061452833142205, 117.43262450694835 34.198818997647145)'
df = spark.createDataFrame([(LINE_WKT,)], ['wkt']) \
.withColumn("line", ST.line_from_text("wkt", 4326))
df.select(ST.geodesic_densify("line", 10000).alias("geodesic_densified")).show(truncate = False)+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|geodesic_densified |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|{"paths":[[[117.61983168124925,34.061452833142205],[117.55749656079557,34.10727359287857],[117.49509421655945,34.153062343775964],[117.43262450694834,34.198818997647145]]]}|
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+Version table
| Release | Notes |
|---|---|
1.1.0 | Python and SQL functions introduced |
1.5.0 | Scala function introduced |