ST_M

ST_M can work as a getter or a setter, depending on the inputs.

Getter: ST_M takes a point column and returns a double column containing the m-values of the input points. If a point does not have an m-value the function returns NaN.

Setter: ST_M takes a point column and a numeric value and returns a point column containing the input points with the m-values set to the numeric value.

Function	Syntax
Python	`m(point, new_value=None)`
SQL	`ST_M(point, new_value)`

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

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

Examples

Getter

Python

SQL

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from geoanalytics.sql import functions as ST

data = [
    ('{"x": -0.126,"y": 51.504,"m": 187.73}',),
    ('{"x": -0.126,"y": 51.504}',)
]

df = spark.createDataFrame(data, ["esri_json"]) \
    .withColumn("point", ST.point_from_esri_json("esri_json"))

df.select(ST.m("point").alias("get_m")).show()

Result-as-getter
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+------+
| get_m|
+------+
|187.73|
|   NaN|
+------+

Setter