ST_Aggr_Linestring

ST_Aggr_Linestring operates on a grouped DataFrame and returns linestrings created from the points in each group. You can group your DataFrame using DataFrame.groupBy() or with a GROUP BY clause in a SQL statement. Points in each group will be connected in the order defined by a numeric column specified with order_by.

FunctionSyntax
Pythonaggr_linestring(geometry, order_by)
SQLST_Aggr_Linestring(geometry, order_by)
ScalaaggrLinestring(geometry, orderBy)

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

Python and SQL Examples

PythonPythonSQL
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from geoanalytics.sql import functions as ST

data = [
    ("POINT (-117.22 33.91)", 1, 1),
    ("POINT (-117.27 34.05)", 1, 0),
    ("POINT (-116.96 33.64)", 1, 2),
    ("POINT (-116.66 33.71)", 1, 3),
    ("POINT (-116.89 33.96)", 2, 0),
    ("POINT (-116.71 34.01)", 2, 1),
    ("POINT (-117.05 34.22)", 2, 3),
    ("POINT (-116.66 34.08)", 2, 2)
]

df = spark.createDataFrame(data, ["wkt", "id", "order"]) \
          .withColumn("point", ST.point_from_text("wkt", srid=4326))

agg_df = df.groupBy("id").agg(ST.aggr_linestring("point", order_by="order").alias("linestring"))

ax = df.st.plot("point", facecolor="none", edgecolor="red", figsize=(15, 8))
agg_df.st.plot("linestring", ax=ax, facecolor="none", edgecolor="blue")
Plotted example for ST_Aggr_Linestring
Plotted result for ST_Aggr_Linestring.

Scala Example

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

case class PointRow(wkt: String, id: Integer, order: Integer)
val data = Seq(PointRow("POINT (-117.22 33.91)", 1, 1),
               PointRow("POINT (-117.27 34.05)", 1, 0),
               PointRow("POINT (-116.96 33.64)", 1, 2),
               PointRow("POINT (-116.66 33.71)", 1, 3),
               PointRow("POINT (-116.89 33.96)", 2, 0),
               PointRow("POINT (-116.71 34.01)", 2, 1),
               PointRow("POINT (-117.05 34.22)", 2, 3),
               PointRow("POINT (-116.66 34.08)", 2, 2))

val df = spark.createDataFrame(data)
              .withColumn("point", ST.pointFromText($"wkt", F.lit(4326)))

val aggDF = df.groupBy($"id").agg(ST.aggrLinestring($"point", $"order").alias("linestring"))

aggDF.show(truncate = false)
Result
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+---+-----------------------------------------------------------------------------+
|id |linestring                                                                   |
+---+-----------------------------------------------------------------------------+
|1  |{"paths":[[[-117.27,34.05],[-117.22,33.91],[-116.96,33.64],[-116.66,33.71]]]}|
|2  |{"paths":[[[-116.89,33.96],[-116.71,34.01],[-116.66,34.08],[-117.05,34.22]]]}|
+---+-----------------------------------------------------------------------------+

Version table

ReleaseNotes

1.2.0

Python and SQL functions introduced

1.5.0

Scala function introduced

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