ST_GeodesicBuffer

ST_GeodesicBuffer takes a geometry column and a numeric distance value and returns a polygon column. The resulting buffer polygons represent the geodesic area that is less than or equal to the specified distance from each input geometry. The result will be in meters.

The distance can be specified with or without a unit.

When specified with a unit, the distance can be defined using ST_CreateDistance or with a tuple containing a number and a unit string (e.g., (10, "kilometers")).

When specified without a unit, the distance can be specified as a single value or a numeric column and is assumed to be in in meters.

This function is more accurate but less performant than ST_Buffer 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_buffer(geometry, distance)`
SQL	`ST_GeodesicBuffer(geometry, distance)`
Python	`geodesicBuffer(geometry, distance)`

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

This function implements the OpenGIS Simple Features Implementation Specification for SQL 1.2.1.

Python and SQL examples

Python

SQL

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from geoanalytics.sql import functions as ST

data = [
    ("POINT (-2533858.73 8107527.81)",),
    ("MULTIPOINT (-3159938.72 8190159.75, -3046133.91 8190159.75, -3188072.29 8103229.92)", ),
    ("LINESTRING (-3636954.77 7750916.26, -3168756.90 7966747.98, -3124795.45 7893415.62)", ),
    ("POLYGON ((-2299937.47 8474247.90, -2543511.83 8425946.52, -2488034.02 8322274.98, -2299937.47 8474247.90))", )
]

df = spark.createDataFrame(data, ["wkt"])\
          .select(ST.geom_from_text("wkt", srid=54008).alias("geometry"))

df = df.withColumn("geodesic_buffer", ST.geodesic_buffer("geometry", 60000))

ax = df.st.plot("geometry", facecolor="none", edgecolor="red")
ax.set_xticklabels(ax.get_xticklabels(),rotation=45)
df.st.plot("geodesic_buffer", ax=ax, facecolor="none", edgecolor="blue")

Plotting example for ST_GeodesicBuffer — Plotted result for ST_GeodesicBuffer.

Scala examples

Scala
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import com.esri.geoanalytics.sql.{functions => ST}
import org.apache.spark.sql.{functions => F}

case class GeometryRow(wkt: String)
val data = Seq(GeometryRow("POINT (-2533858.73 8107527.81)"),
               GeometryRow("MULTIPOINT (-3159938.72 8190159.75, -3046133.91 8190159.75, -3188072.29 8103229.92)"),
               GeometryRow("LINESTRING (-3636954.77 7750916.26, -3168756.90 7966747.98, -3124795.45 7893415.62)"),
               GeometryRow("POLYGON ((-2299937.47 8474247.90, -2543511.83 8425946.52, -2488034.02 8322274.98, -2299937.47 8474247.90))"))

val df = spark.createDataFrame(data)
              .select(ST.geomFromText($"wkt", F.lit(54008)).alias("geometry"))
              .withColumn("geodesic_buffer", ST.geodesicBuffer($"geometry", 60000))
              .withColumn("buffer_area", F.round(ST.geodesicArea($"geodesic_buffer"),3))

df.select("geodesic_buffer", "buffer_area").show()

Result
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+--------------------+------------------+
|     geodesic_buffer|       buffer_area|
+--------------------+------------------+
|{"rings":[[[-2455...|1.1288992603518E10|
|{"rings":[[[-2947...|3.1841572796083E10|
|{"rings":[[[-3641...|6.1757784805281E10|
|{"rings":[[[-2222...|5.9119409521289E10|
+--------------------+------------------+

Version table

Release	Notes
1.0.0	Python and SQL functions introduced
1.5.0	Scala function introduced
1.6.0	`distance` parameter accepts values with specified units

ST_GeodesicBuffer

Python and SQL examples

Scala examples

Version table

Related topics