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Spatial SQL app

The page outlines the steps to manage spatial data using SedonaSQL.

Note

Sedona assumes geographic coordinates to be in longitude/latitude order. If your data is lat/lon order, please use ST_FlipCoordinates to swap X and Y.

SedonaSQL supports SQL/MM Part3 Spatial SQL Standard. It includes four kinds of SQL operators as follows. All these operators can be directly called through:

var myDataFrame = sedona.sql("YOUR_SQL")
myDataFrame.createOrReplaceTempView("spatialDf")

Dataset<Row> myDataFrame = sedona.sql("YOUR_SQL")
myDataFrame.createOrReplaceTempView("spatialDf")

myDataFrame = sedona.sql("YOUR_SQL")
myDataFrame.createOrReplaceTempView("spatialDf")

Detailed SedonaSQL APIs are available here: SedonaSQL API. You can find example county data (i.e., county_small.tsv) in Sedona GitHub repo.

Set up dependencies

  1. Read Sedona Maven Central coordinates and add Sedona dependencies in build.sbt or pom.xml.
  2. Add Apache Spark core, Apache SparkSQL in build.sbt or pom.xml.
  3. Please see SQL example project
  1. Please read Quick start to install Sedona Python.
  2. This tutorial is based on Sedona SQL Jupyter Notebook example. You can interact with Sedona Python Jupyter notebook immediately on Binder. Click Binder to interact with Sedona Python Jupyter notebook immediately on Binder.

Create Sedona config

Use the following code to create your Sedona config at the beginning. If you already have a SparkSession (usually named spark) created by AWS EMR/Databricks/Microsoft Fabric, please skip this step.

You can add additional Spark runtime config to the config builder. For example, SedonaContext.builder().config("spark.sql.autoBroadcastJoinThreshold", "10485760")

import org.apache.sedona.spark.SedonaContext

val config = SedonaContext.builder()
.master("local[*]") // Delete this if run in cluster mode
.appName("readTestScala") // Change this to a proper name
.getOrCreate()
If you use SedonaViz together with SedonaSQL, please add the following line after SedonaContext.builder() to enable Sedona Kryo serializer: 
.config("spark.kryo.registrator", classOf[SedonaVizKryoRegistrator].getName) // org.apache.sedona.viz.core.Serde.SedonaVizKryoRegistrator


import org.apache.sedona.spark.SedonaContext;

SparkSession config = SedonaContext.builder()
.master("local[*]") // Delete this if run in cluster mode
.appName("readTestJava") // Change this to a proper name
.getOrCreate()
If you use SedonaViz together with SedonaSQL, please add the following line after SedonaContext.builder() to enable Sedona Kryo serializer: 
.config("spark.kryo.registrator", SedonaVizKryoRegistrator.class.getName()) // org.apache.sedona.viz.core.Serde.SedonaVizKryoRegistrator


from sedona.spark import *

config = SedonaContext.builder() .\
    config('spark.jars.packages',
           'org.apache.sedona:sedona-spark-shaded-3.3_2.12:1.7.0,'
           'org.datasyslab:geotools-wrapper:1.7.0-28.5'). \
    getOrCreate()
If you are using a different Spark version, please replace the 3.3 in package name of sedona-spark-shaded with the corresponding major.minor version of Spark, such as sedona-spark-shaded-3.4_2.12:1.7.0.

Initiate SedonaContext

Add the following line after creating Sedona config. If you already have a SparkSession (usually named spark) created by AWS EMR/Databricks/Microsoft Fabric, please call sedona = SedonaContext.create(spark) instead. For Databricks, the situation is more complicated, please refer to Databricks setup guide, but generally you don't need to create SedonaContext.

import org.apache.sedona.spark.SedonaContext

val sedona = SedonaContext.create(config)

import org.apache.sedona.spark.SedonaContext;

SparkSession sedona = SedonaContext.create(config)

from sedona.spark import *

sedona = SedonaContext.create(config)

You can also register everything by passing --conf spark.sql.extensions=org.apache.sedona.sql.SedonaSqlExtensions to spark-submit or spark-shell.

Load data from text files

Assume we have a WKT file, namely usa-county.tsv, at Path /Download/usa-county.tsv as follows:

POLYGON (..., ...)  Cuming County
POLYGON (..., ...)  Wahkiakum County
POLYGON (..., ...)  De Baca County
POLYGON (..., ...)  Lancaster County

The file may have many other columns.

Load the raw DataFrame

Use the following code to load the data and create a raw DataFrame:

var rawDf = sedona.read.format("csv").option("delimiter", "\t").option("header", "false").load("/Download/usa-county.tsv")
rawDf.createOrReplaceTempView("rawdf")
rawDf.show()

Dataset<Row> rawDf = sedona.read.format("csv").option("delimiter", "\t").option("header", "false").load("/Download/usa-county.tsv")
rawDf.createOrReplaceTempView("rawdf")
rawDf.show()

rawDf = sedona.read.format("csv").option("delimiter", "\t").option("header", "false").load("/Download/usa-county.tsv")
rawDf.createOrReplaceTempView("rawdf")
rawDf.show()

The output will be like this:

|                 _c0|_c1|_c2|     _c3|  _c4|        _c5|                 _c6|_c7|_c8|  _c9|_c10| _c11|_c12|_c13|      _c14|    _c15|       _c16|        _c17|
+--------------------+---+---+--------+-----+-----------+--------------------+---+---+-----+----+-----+----+----+----------+--------+-----------+------------+
|POLYGON ((-97.019...| 31|039|00835841|31039|     Cuming|       Cuming County| 06| H1|G4020|null| null|null|   A|1477895811|10447360|+41.9158651|-096.7885168|
|POLYGON ((-123.43...| 53|069|01513275|53069|  Wahkiakum|    Wahkiakum County| 06| H1|G4020|null| null|null|   A| 682138871|61658258|+46.2946377|-123.4244583|
|POLYGON ((-104.56...| 35|011|00933054|35011|    De Baca|      De Baca County| 06| H1|G4020|null| null|null|   A|6015539696|29159492|+34.3592729|-104.3686961|
|POLYGON ((-96.910...| 31|109|00835876|31109|  Lancaster|    Lancaster County| 06| H1|G4020| 339|30700|null|   A|2169240202|22877180|+40.7835474|-096.6886584|

Create a Geometry type column

All geometrical operations in SedonaSQL are on Geometry type objects. Therefore, before any kind of queries, you need to create a Geometry type column on a DataFrame.

SELECT ST_GeomFromWKT(_c0) AS countyshape, _c1, _c2

You can select many other attributes to compose this spatialdDf. The output will be something like this:

|                 countyshape|_c1|_c2|     _c3|  _c4|        _c5|                 _c6|_c7|_c8|  _c9|_c10| _c11|_c12|_c13|      _c14|    _c15|       _c16|        _c17|
+--------------------+---+---+--------+-----+-----------+--------------------+---+---+-----+----+-----+----+----+----------+--------+-----------+------------+
|POLYGON ((-97.019...| 31|039|00835841|31039|     Cuming|       Cuming County| 06| H1|G4020|null| null|null|   A|1477895811|10447360|+41.9158651|-096.7885168|
|POLYGON ((-123.43...| 53|069|01513275|53069|  Wahkiakum|    Wahkiakum County| 06| H1|G4020|null| null|null|   A| 682138871|61658258|+46.2946377|-123.4244583|
|POLYGON ((-104.56...| 35|011|00933054|35011|    De Baca|      De Baca County| 06| H1|G4020|null| null|null|   A|6015539696|29159492|+34.3592729|-104.3686961|
|POLYGON ((-96.910...| 31|109|00835876|31109|  Lancaster|    Lancaster County| 06| H1|G4020| 339|30700|null|   A|2169240202|22877180|+40.7835474|-096.6886584|

Although it looks same with the input, but actually the type of column countyshape has been changed to Geometry type.

To verify this, use the following code to print the schema of the DataFrame:

spatialDf.printSchema()

The output will be like this:

root
 |-- countyshape: geometry (nullable = false)
 |-- _c1: string (nullable = true)
 |-- _c2: string (nullable = true)
 |-- _c3: string (nullable = true)
 |-- _c4: string (nullable = true)
 |-- _c5: string (nullable = true)
 |-- _c6: string (nullable = true)
 |-- _c7: string (nullable = true)

Note

SedonaSQL provides lots of functions to create a Geometry column, please read SedonaSQL constructor API.

Load GeoJSON Data

Since v1.6.1, Sedona supports reading GeoJSON files using the geojson data source. It is designed to handle JSON files that use GeoJSON format for their geometries.

Set the multiLine option to True to read multiline GeoJSON files.

df = sedona.read.format("geojson").option("multiLine", "true").load("PATH/TO/MYFILE.json")
 .selectExpr("explode(features) as features") # Explode the envelope to get one feature per row.
 .select("features.*") # Unpack the features struct.
 .withColumn("prop0", f.expr("properties['prop0']")).drop("properties").drop("type")

df.show()
df.printSchema()

val df = sedona.read.format("geojson").option("multiLine", "true").load("PATH/TO/MYFILE.json")
val parsedDf = df.selectExpr("explode(features) as features").select("features.*")
        .withColumn("prop0", expr("properties['prop0']")).drop("properties").drop("type")

parsedDf.show()
parsedDf.printSchema()

Dataset<Row> df = sedona.read.format("geojson").option("multiLine", "true").load("PATH/TO/MYFILE.json")
 .selectExpr("explode(features) as features") // Explode the envelope to get one feature per row.
 .select("features.*") // Unpack the features struct.
 .withColumn("prop0", expr("properties['prop0']")).drop("properties").drop("type")

df.show();
df.printSchema();

See this page for more information on loading GeoJSON files.

Load Shapefile

Since v1.7.0, Sedona supports loading Shapefile as a DataFrame.

val df = sedona.read.format("shapefile").load("/path/to/shapefile")

Dataset<Row> df = sedona.read().format("shapefile").load("/path/to/shapefile")

df = sedona.read.format("shapefile").load("/path/to/shapefile")

The input path can be a directory containing one or multiple shapefiles, or path to a .shp file.

See this page for more information on loading Shapefiles.

Load GeoParquet

Since v1.3.0, Sedona natively supports loading GeoParquet file. Sedona will infer geometry fields using the "geo" metadata in GeoParquet files.

val df = sedona.read.format("geoparquet").load(geoparquetdatalocation1)
df.printSchema()

Dataset<Row> df = sedona.read.format("geoparquet").load(geoparquetdatalocation1)
df.printSchema()

df = sedona.read.format("geoparquet").load(geoparquetdatalocation1)
df.printSchema()

The output will be as follows:

root
 |-- pop_est: long (nullable = true)
 |-- continent: string (nullable = true)
 |-- name: string (nullable = true)
 |-- iso_a3: string (nullable = true)
 |-- gdp_md_est: double (nullable = true)
 |-- geometry: geometry (nullable = true)

Sedona supports spatial predicate push-down for GeoParquet files, please refer to the SedonaSQL query optimizer documentation for details.

GeoParquet file reader can also be used to read legacy Parquet files written by Apache Sedona 1.3.1-incubating or earlier. Please refer to Reading Legacy Parquet Files for details.

Warning

GeoParquet file reader does not work on Databricks runtime when Photon is enabled. Please disable Photon when using GeoParquet file reader on Databricks runtime.

See this page for more information on loading GeoParquet.

Load data from STAC catalog

Sedona STAC data source allows you to read data from a SpatioTemporal Asset Catalog (STAC) API. The data source supports reading STAC items and collections.

You can load a STAC collection from a s3 collection file object:

df = sedona.read.format("stac").load(
    "s3a://example.com/stac_bucket/stac_collection.json"
)

You can also load a STAC collection from an HTTP/HTTPS endpoint:

df = sedona.read.format("stac").load(
    "https://earth-search.aws.element84.com/v1/collections/sentinel-2-pre-c1-l2a"
)

The STAC data source supports predicate pushdown for spatial and temporal filters. The data source can push down spatial and temporal filters to the underlying data source to reduce the amount of data that needs to be read.

See this page for more information on loading data from STAC.

Load data from JDBC data sources

The 'query' option in Spark SQL's JDBC data source can be used to convert geometry columns to a format that Sedona can interpret. This should work for most spatial JDBC data sources. For Postgis there is no need to add a query to convert geometry types since it's already using EWKB as it's wire format.

// For any JDBC data source, including Postgis.
val df = sedona.read.format("jdbc")
    // Other options.
    .option("query", "SELECT id, ST_AsBinary(geom) as geom FROM my_table")
    .load()
    .withColumn("geom", expr("ST_GeomFromWKB(geom)"))

// This is a simplified version that works for Postgis.
val df = sedona.read.format("jdbc")
    // Other options.
    .option("dbtable", "my_table")
    .load()
    .withColumn("geom", expr("ST_GeomFromWKB(geom)"))

// For any JDBC data source, including Postgis.
Dataset<Row> df = sedona.read().format("jdbc")
    // Other options.
    .option("query", "SELECT id, ST_AsBinary(geom) as geom FROM my_table")
    .load()
    .withColumn("geom", expr("ST_GeomFromWKB(geom)"))

// This is a simplified version that works for Postgis.
Dataset<Row> df = sedona.read().format("jdbc")
    // Other options.
    .option("dbtable", "my_table")
    .load()
    .withColumn("geom", expr("ST_GeomFromWKB(geom)"))

# For any JDBC data source, including Postgis.
df = (sedona.read.format("jdbc")
    # Other options.
    .option("query", "SELECT id, ST_AsBinary(geom) as geom FROM my_table")
    .load()
    .withColumn("geom", f.expr("ST_GeomFromWKB(geom)")))

# This is a simplified version that works for Postgis.
df = (sedona.read.format("jdbc")
    # Other options.
    .option("dbtable", "my_table")
    .load()
    .withColumn("geom", f.expr("ST_GeomFromWKB(geom)")))

Load GeoPackage

Since v1.7.0, Sedona supports loading Geopackage file format as a DataFrame.

val df = sedona.read.format("geopackage").option("tableName", "tab").load("/path/to/geopackage")

Dataset<Row> df = sedona.read().format("geopackage").option("tableName", "tab").load("/path/to/geopackage")

df = sedona.read.format("geopackage").option("tableName", "tab").load("/path/to/geopackage")

See this page for more information on loading GeoPackage.

Load OSM PBF

Since v1.7.1, Sedona supports loading OSM PBF file format as a DataFrame.

val df = sedona.read.format("osmpbf").load("/path/to/osmpbf")

Dataset<Row> df = sedona.read().format("osmpbf").load("/path/to/osmpbf")

df = sedona.read.format("osmpbf").load("/path/to/osmpbf")

OSM PBF files can contain nodes, ways, and relations. Currently Sedona support DenseNodes, Ways and Relations. When you load the data you get a DataFrame with the following schema.

root
 |-- id: long (nullable = true)
 |-- kind: string (nullable = true)
 |-- location: struct (nullable = true)
 |    |-- longitude: double (nullable = true)
 |    |-- latitude: double (nullable = true)
 |-- tags: map (nullable = true)
 |    |-- key: string
 |    |-- value: string (valueContainsNull = true)
 |-- refs: array (nullable = true)
 |    |-- element: long (containsNull = true)
 |-- ref_roles: array (nullable = true)
 |    |-- element: string (containsNull = true)
 |-- ref_types: array (nullable = true)
 |    |-- element: string (containsNull = true)

Where:

  • id is the unique identifier of the object.
  • kind is the type of the object, it can be node, way or relation.
  • location is the location of the object, it contains the longitude and latitude of the object.
  • tags is a map of key-value pairs that represent the tags of the object.
  • refs is an array of the references of the object.
  • ref_roles is an array of the roles of the references.
  • ref_types is an array of the types of the references.

The dataframe for ways might look like this for nodes:

+---------+----+--------------------+--------------------+----+---------+---------+
|       id|kind|            location|                tags|refs|ref_roles|ref_types|
+---------+----+--------------------+--------------------+----+---------+---------+
|248675410|node|{21.0884952545166...|{tactile_paving -...|NULL|     NULL|     NULL|
|260821820|node|{21.0191555023193...|{created_by -> JOSM}|NULL|     NULL|     NULL|
|349189665|node|{22.1437530517578...|{source -> http:/...|NULL|     NULL|     NULL|
|353366899|node|{22.9787712097167...|{source -> http:/...|NULL|     NULL|     NULL|
|359460224|node|{22.4816703796386...|{source -> http:/...|NULL|     NULL|     NULL|
+---------+----+--------------------+--------------------+----+---------+---------+
only showing top 5 rows

and for way

+-------+----+--------+--------------------+--------------------+---------+---------+
|     id|kind|location|                tags|                refs|ref_roles|ref_types|
+-------+----+--------+--------------------+--------------------+---------+---------+
|4307329| way|    NULL|{junction -> roun...|[2448759046, 7093...|     NULL|     NULL|
|4307330| way|    NULL|{surface -> aspha...|[26063923, 260639...|     NULL|     NULL|
|4308966| way|    NULL|{sidewalk -> sepa...|[3387797238, 9252...|     NULL|     NULL|
|4308968| way|    NULL|{surface -> pavin...|[26083890, 744724...|     NULL|     NULL|
|4308969| way|    NULL|{cycleway:both ->...|[9526831176, 1218...|     NULL|     NULL|
+-------+----+--------+--------------------+--------------------+---------+---------+

and for relation

+-----+--------+--------+--------------------+--------------------+--------------------+--------------------+
|   id|    kind|location|                tags|                refs|           ref_roles|           ref_types|
+-----+--------+--------+--------------------+--------------------+--------------------+--------------------+
|28124|relation|    NULL|{official_name ->...|[26382394, 26259985]|      [inner, outer]|          [WAY, WAY]|
|28488|relation|    NULL|  {type -> junction}|[26409253, 303249...|[roundabout, roun...|[WAY, WAY, WAY, WAY]|
|32939|relation|    NULL|{ref -> E 67, rou...|[140673970, 14067...|        [, , , , , ]|[WAY, WAY, RELATI...|
|34387|relation|    NULL|{note -> rząd III...|[209161000, 52154...|[main_stream, mai...|[WAY, WAY, WAY, W...|
|34392|relation|    NULL|{distance -> 1047...|[150033976, 25076...|[main_stream, mai...|[WAY, WAY, WAY, W...|
+-----+--------+--------+--------------------+--------------------+--------------------+--------------------+

Transform the Coordinate Reference System

Sedona doesn't control the coordinate unit (degree-based or meter-based) of all geometries in a Geometry column. The unit of all related distances in SedonaSQL is same as the unit of all geometries in a Geometry column.

By default, this function uses lon/lat order since v1.5.0. Before, it used lat/lon order. You can use ST_FlipCoordinates to swap X and Y.

For more details, please read the ST_Transform section in Sedona API References.

To convert Coordinate Reference System of the Geometry column created before, use the following code:

SELECT ST_Transform(countyshape, "epsg:4326", "epsg:3857") AS newcountyshape, _c1, _c2, _c3, _c4, _c5, _c6, _c7
FROM spatialdf

The first EPSG code EPSG:4326 in ST_Transform is the source CRS of the geometries. It is WGS84, the most common degree-based CRS.

The second EPSG code EPSG:3857 in ST_Transform is the target CRS of the geometries. It is the most common meter-based CRS.

This ST_Transform transform the CRS of these geometries from EPSG:4326 to EPSG:3857. The details CRS information can be found on EPSG.io

The coordinates of polygons have been changed. The output will be like this:

+--------------------+---+---+--------+-----+-----------+--------------------+---+
|      newcountyshape|_c1|_c2|     _c3|  _c4|        _c5|                 _c6|_c7|
+--------------------+---+---+--------+-----+-----------+--------------------+---+
|POLYGON ((-108001...| 31|039|00835841|31039|     Cuming|       Cuming County| 06|
|POLYGON ((-137408...| 53|069|01513275|53069|  Wahkiakum|    Wahkiakum County| 06|
|POLYGON ((-116403...| 35|011|00933054|35011|    De Baca|      De Baca County| 06|
|POLYGON ((-107880...| 31|109|00835876|31109|  Lancaster|    Lancaster County| 06|

Cluster with DBSCAN

Sedona provides an implementation of the DBSCAN algorithm to cluster spatial data.

The algorithm is available as a Scala and Python function called on a spatial dataframe. The returned dataframe has an additional column added containing the unique identifier of the cluster that record is a member of and a boolean column indicating if the record is a core point.

The first parameter is the dataframe, the next two are the epsilon and min_points parameters of the DBSCAN algorithm.

import org.apache.sedona.stats.clustering.DBSCAN.dbscan

dbscan(df, 0.1, 5).show()

import org.apache.sedona.stats.clustering.DBSCAN;

DBSCAN.dbscan(df, 0.1, 5).show();

from sedona.stats.clustering.dbscan import dbscan

dbscan(df, 0.1, 5).show()

The output will look like this:

+----------------+---+------+-------+
|        geometry| id|isCore|cluster|
+----------------+---+------+-------+
|   POINT (2.5 4)|  3| false|      1|
|     POINT (3 4)|  2| false|      1|
|     POINT (3 5)|  5| false|      1|
|     POINT (1 3)|  9|  true|      0|
| POINT (2.5 4.5)|  7|  true|      1|
|     POINT (1 2)|  1|  true|      0|
| POINT (1.5 2.5)|  4|  true|      0|
| POINT (1.2 2.5)|  8|  true|      0|
|   POINT (1 2.5)| 11|  true|      0|
|     POINT (1 5)| 10| false|     -1|
|     POINT (5 6)| 12| false|     -1|
|POINT (12.8 4.5)|  6| false|     -1|
|     POINT (4 3)| 13| false|     -1|
+----------------+---+------+-------+

See this page for more information on the DBSCAN algorithm.

Calculate the Local Outlier Factor (LOF)

Sedona provides an implementation of the Local Outlier Factor algorithm to identify anomalous data.

The algorithm is available as a Scala and Python function called on a spatial dataframe. The returned dataframe has an additional column added containing the local outlier factor.

The first parameter is the dataframe, the next is the number of nearest neighbors to consider use in calculating the score.

import org.apache.sedona.stats.outlierDetection.LocalOutlierFactor.localOutlierFactor

localOutlierFactor(df, 20).show()

import org.apache.sedona.stats.outlierDetection.LocalOutlierFactor;

LocalOutlierFactor.localOutlierFactor(df, 20).show();

from sedona.stats.outlier_detection.local_outlier_factor import local_outlier_factor

local_outlier_factor(df, 20).show()

The output will look like this:

+--------------------+------------------+
|            geometry|               lof|
+--------------------+------------------+
|POINT (-2.0231305...| 0.952098153363662|
|POINT (-2.0346944...|0.9975325496668104|
|POINT (-2.2040074...|1.0825843906411081|
|POINT (1.61573501...|1.7367129352162634|
|POINT (-2.1176324...|1.5714144683150393|
|POINT (-2.2349759...|0.9167275845938276|
|POINT (1.65470192...| 1.046231536764447|
|POINT (0.62624112...|1.1988700676990034|
|POINT (2.01746261...|1.1060219481067417|
|POINT (-2.0483857...|1.0775553430145446|
|POINT (2.43969463...|1.1129132178576646|
|POINT (-2.2425480...| 1.104108012697006|
|POINT (-2.7859235...|  2.86371824574529|
|POINT (-1.9738858...|1.0398822680356794|
|POINT (2.00153403...| 0.927409656346015|
|POINT (2.06422812...|0.9222203762264445|
|POINT (-1.7533819...|1.0273650471626696|
|POINT (-2.2030766...| 0.964744555830738|
|POINT (-1.8509857...|1.0375927869698574|
|POINT (2.10849080...|1.0753419197322656|
+--------------------+------------------+

Perform Getis-Ord Gi(*) Hot Spot Analysis

Sedona provides an implementation of the Gi and Gi* algorithms to identify local hotspots in spatial data

The algorithm is available as a Scala and Python function called on a spatial dataframe. The returned dataframe has additional columns added containing G statistic, E[G], V[G], the Z score, and the p-value.

Using Gi involves first generating the neighbors list for each record, then calling the g_local function.

import org.apache.sedona.stats.Weighting.addBinaryDistanceBandColumn
import org.apache.sedona.stats.hotspotDetection.GetisOrd.gLocal

val distanceRadius = 1.0
val weightedDf = addBinaryDistanceBandColumn(df, distanceRadius)
gLocal(weightedDf, "val").show()

import org.apache.sedona.stats.Weighting;
import org.apache.sedona.stats.hotspotDetection.GetisOrd;
import org.apache.spark.sql.DataFrame;

double distanceRadius = 1.0;
DataFrame weightedDf = Weighting.addBinaryDistanceBandColumn(df, distanceRadius);
GetisOrd.gLocal(weightedDf, "val").show();

from sedona.stats.weighting import add_binary_distance_band_column
from sedona.stats.hotspot_detection.getis_ord import g_local

distance_radius = 1.0
weighted_df = addBinaryDistanceBandColumn(df, distance_radius)
g_local(weightedDf, "val").show()

The output will look like this:


+-----------+---+--------------------+-------------------+-------------------+--------------------+--------------------+--------------------+
|   geometry|val|             weights|                  G|                 EG|                  VG|                   Z|                   P|
+-----------+---+--------------------+-------------------+-------------------+--------------------+--------------------+--------------------+
|POINT (2 2)|0.9|[{{POINT (2 3), 1...| 0.4488188976377953|0.45454545454545453| 0.00356321373799772|-0.09593402008347063|  0.4617864875295957|
|POINT (2 3)|1.2|[{{POINT (2 2), 0...|0.35433070866141736|0.36363636363636365|0.003325666155464539|-0.16136436037034918|  0.4359032175415549|
|POINT (3 3)|1.2|[{{POINT (2 3), 1...|0.28346456692913385| 0.2727272727272727|0.002850570990398176| 0.20110780337013057| 0.42030714022155924|
|POINT (3 2)|1.2|[{{POINT (2 2), 0...| 0.4488188976377953|0.45454545454545453| 0.00356321373799772|-0.09593402008347063|  0.4617864875295957|
|POINT (3 1)|1.2|[{{POINT (3 2), 3...| 0.3622047244094489| 0.2727272727272727|0.002850570990398176|  1.6758983614177538| 0.04687905137429871|
|POINT (2 1)|2.2|[{{POINT (2 2), 0...| 0.4330708661417323|0.36363636363636365|0.003325666155464539|  1.2040263812249166| 0.11428969105925013|
|POINT (1 1)|1.2|[{{POINT (2 1), 5...| 0.2834645669291339| 0.2727272727272727|0.002850570990398176|  0.2011078033701316|  0.4203071402215588|
|POINT (1 2)|0.2|[{{POINT (2 2), 0...|0.35433070866141736|0.45454545454545453| 0.00356321373799772|   -1.67884535146075|0.046591093685710794|
|POINT (1 3)|1.2|[{{POINT (2 3), 1...| 0.2047244094488189| 0.2727272727272727|0.002850570990398176| -1.2736827546774914| 0.10138793530151635|
|POINT (0 2)|1.0|[{{POINT (1 2), 7...|0.09448818897637795|0.18181818181818182|0.002137928242798632| -1.8887168824332323|0.029464887612748458|
|POINT (4 2)|1.2|[{{POINT (3 2), 3...| 0.1889763779527559|0.18181818181818182|0.002137928242798632| 0.15481285921583854| 0.43848442662481324|
+-----------+---+--------------------+-------------------+-------------------+--------------------+--------------------+--------------------+

Run spatial queries

After creating a Geometry type column, you are able to run spatial queries.

Range query

Use ST_Contains, ST_Intersects, ST_Within to run a range query over a single column.

The following example finds all counties that are within the given polygon:

SELECT *
FROM spatialdf
WHERE ST_Contains (ST_PolygonFromEnvelope(1.0,100.0,1000.0,1100.0), newcountyshape)

Note

Read SedonaSQL constructor API to learn how to create a Geometry type query window

KNN query

Use ST_Distance to calculate the distance and rank the distance.

The following code returns the 5 nearest neighbor of the given polygon.

SELECT countyname, ST_Distance(ST_PolygonFromEnvelope(1.0,100.0,1000.0,1100.0), newcountyshape) AS distance
FROM spatialdf
ORDER BY distance DESC
LIMIT 5

Join query

The details of a join query is available here Join query.

KNN join query

The details of a KNN join query is available here KNN join query.

Other queries

There are lots of other functions can be combined with these queries. Please read SedonaSQL functions and SedonaSQL aggregate functions.

Visualize query results

Sedona provides SedonaPyDeck and SedonaKepler wrappers, both of which expose APIs to create interactive map visualizations from SedonaDataFrames in a Jupyter environment.

Note

Both SedonaPyDeck and SedonaKepler expect the default geometry order to be lon-lat. If your dataframe has geometries in the lat-lon order, please check out ST_FlipCoordinates

Note

Both SedonaPyDeck and SedonaKepler are designed to work with SedonaDataFrames containing only 1 geometry column. Passing dataframes with multiple geometry columns will cause errors.

SedonaPyDeck

Spatial query results can be visualized in a Jupyter lab/notebook environment using SedonaPyDeck.

SedonaPyDeck exposes APIs to create interactive map visualizations using pydeck based on deck.gl

Note

To use SedonaPyDeck, install sedona with the pydeck-map extra: 

pip install apache-sedona[pydeck-map]

The following tutorial showcases the various maps that can be created using SedonaPyDeck, the datasets used to create these maps are publicly available.

Each API exposed by SedonaPyDeck offers customization via optional arguments, details on all possible arguments can be found in the API docs of SedonaPyDeck.

Creating a Choropleth map using SedonaPyDeck

SedonaPyDeck exposes a create_choropleth_map API which can be used to visualize a choropleth map out of the passed SedonaDataFrame containing polygons with an observation:

Example (referenced from example notebook available via binder):

SedonaPyDeck.create_choropleth_map(df=groupedresult, plot_col='AirportCount')

Note

plot_col is a required argument informing SedonaPyDeck of the column name used to render the choropleth effect.

Creating a Choropleth map using SedonaPyDeck

The dataset used is available here and can also be found in the example notebook available here

Creating a Geometry map using SedonaPyDeck

SedonaPyDeck exposes a create_geometry_map API which can be used to visualize a passed SedonaDataFrame containing any type of geometries:

Example (referenced from overture notebook available via binder):

SedonaPyDeck.create_geometry_map(df_building, elevation_col='height')

Creating a Geometry map using SedonaPyDeck

Tip

elevation_col is an optional argument which can be used to render a 3D map. Pass the column with 'elevation' values for the geometries here.

Creating a Scatterplot map using SedonaPyDeck

SedonaPyDeck exposes a create_scatterplot_map API which can be used to visualize a scatterplot out of the passed SedonaDataFrame containing points:

Example:

SedonaPyDeck.create_scatterplot_map(df=crimes_df)

Creating a Scatterplot map using SedonaPyDeck

The dataset used here is the Chicago crimes dataset, available here

Creating a heatmap using SedonaPyDeck

SedonaPyDeck exposes a create_heatmap API which can be used to visualize a heatmap out of the passed SedonaDataFrame containing points:

Example:

SedonaPyDeck.create_heatmap(df=crimes_df)

Creating a heatmap using SedonaPyDeck

The dataset used here is the Chicago crimes dataset, available here

SedonaKepler

Spatial query results can be visualized in a Jupyter lab/notebook environment using SedonaKepler.

SedonaKepler exposes APIs to create interactive and customizable map visualizations using KeplerGl.

Note

To use SedonaKepler, install sedona with the kepler-map extra: 

pip install apache-sedona[kepler-map]

This tutorial showcases how simple it is to instantly visualize geospatial data using SedonaKepler.

Example (referenced from an example notebook via the binder):

SedonaKepler.create_map(df=groupedresult, name="AirportCount")

Visualize geospatial data using SedonaKepler

The dataset used is available here and can also be found in the example notebook available here

Details on all the APIs available by SedonaKepler are listed in the SedonaKepler API docs

Create a User-Defined Function (UDF)

User-Defined Functions (UDFs) are user-created procedures that can perform operations on a single row of information. To cover almost all use cases, we will showcase 4 types of UDFs for a better understanding of how to use geometry with UDFs. Sedona's serializer deserializes the SQL geometry type to JTS Geometry (Scala/Java) or Shapely Geometry (Python). You can implement any custom logic using the rich ecosystem around these two libraries.

Geometry to primitive

This UDF example takes a geometry type input and returns a primitive type output:

import org.locationtech.jts.geom.Geometry
import org.apache.spark.sql.types._

def lengthPoly(geom: Geometry): Double = {
    geom.getLength
}

sedona.udf.register("udf_lengthPoly", lengthPoly _)

df.selectExpr("udf_lengthPoly(geom)").show()

import org.apache.spark.sql.api.java.UDF1;
import org.apache.spark.sql.types.DataTypes;

// using lambda function to register the UDF
sparkSession.udf().register(
        "udf_lengthPoly",
        (UDF1<Geometry, Double>) Geometry::getLength,
        DataTypes.DoubleType);

df.selectExpr("udf_lengthPoly(geom)").show()

from sedona.sql.types import GeometryType
from pyspark.sql.types import DoubleType

def lengthPoly(geom: GeometryType()):
    return geom.length

sedona.udf.register("udf_lengthPoly", lengthPoly, DoubleType())

df.selectExpr("udf_lengthPoly(geom)").show()

Output:

+--------------------+
|udf_lengthPoly(geom)|
+--------------------+
|   3.414213562373095|
+--------------------+

Geometry to Geometry

This UDF example takes a geometry type input and returns a geometry type output:

import org.locationtech.jts.geom.Geometry
import org.apache.spark.sql.types._

def bufferFixed(geom: Geometry): Geometry = {
    geom.buffer(5.5)
}

sedona.udf.register("udf_bufferFixed", bufferFixed _)

df.selectExpr("udf_bufferFixed(geom)").show()

import org.apache.spark.sql.api.java.UDF1;
import org.apache.spark.sql.types.DataTypes;

// using lambda function to register the UDF
sparkSession.udf().register(
        "udf_bufferFixed",
        (UDF1<Geometry, Geometry>) geom ->
            geom.buffer(5.5),
        new GeometryUDT());

df.selectExpr("udf_bufferFixed(geom)").show()

from sedona.sql.types import GeometryType
from pyspark.sql.types import DoubleType

def bufferFixed(geom: GeometryType()):
    return geom.buffer(5.5)

sedona.udf.register("udf_bufferFixed", bufferFixed, GeometryType())

df.selectExpr("udf_bufferFixed(geom)").show()

Output:

+--------------------------------------------------+
|                             udf_bufferFixed(geom)|
+--------------------------------------------------+
|POLYGON ((1 -4.5, -0.0729967710887076 -4.394319...|
+--------------------------------------------------+

Geometry, primitive to geometry

This UDF example takes a geometry type input and a primitive type input and returns a geometry type output:

import org.locationtech.jts.geom.Geometry
import org.apache.spark.sql.types._

def bufferIt(geom: Geometry, distance: Double): Geometry = {
    geom.buffer(distance)
}

sedona.udf.register("udf_buffer", bufferIt _)

df.selectExpr("udf_buffer(geom, distance)").show()

import org.apache.spark.sql.api.java.UDF2;
import org.apache.spark.sql.types.DataTypes;

// using lambda function to register the UDF
sparkSession.udf().register(
        "udf_buffer",
        (UDF2<Geometry, Double, Geometry>) Geometry::buffer,
        new GeometryUDT());

df.selectExpr("udf_buffer(geom, distance)").show()

from sedona.sql.types import GeometryType
from pyspark.sql.types import DoubleType

def bufferIt(geom: GeometryType(), distance: DoubleType()):
    return geom.buffer(distance)

sedona.udf.register("udf_buffer", bufferIt, GeometryType())

df.selectExpr("udf_buffer(geom, distance)").show()

Output:

+--------------------------------------------------+
|                        udf_buffer(geom, distance)|
+--------------------------------------------------+
|POLYGON ((1 -9, -0.9509032201612866 -8.80785280...|
+--------------------------------------------------+

Geometry, primitive to Geometry, primitive

This UDF example takes a geometry type input and a primitive type input and returns a geometry type and a primitive type output:

import org.locationtech.jts.geom.Geometry
import org.apache.spark.sql.types._
import org.apache.spark.sql.api.java.UDF2

val schemaUDF = StructType(Array(
    StructField("buffed", GeometryUDT),
    StructField("length", DoubleType)
))

val udf_bufferLength = udf(
    new UDF2[Geometry, Double, (Geometry, Double)] {
        def call(geom: Geometry, distance: Double): (Geometry, Double) = {
            val buffed = geom.buffer(distance)
            val length = geom.getLength
            (buffed, length)
        }
    }, schemaUDF)

sedona.udf.register("udf_bufferLength", udf_bufferLength)

data.withColumn("bufferLength", expr("udf_bufferLengths(geom, distance)"))
    .select("geom", "distance", "bufferLength.*")
    .show()

import org.apache.spark.sql.api.java.UDF2;
import org.apache.spark.sql.types.DataTypes;
import org.apache.spark.sql.types.StructType;
import scala.Tuple2;

StructType schemaUDF = new StructType()
            .add("buffedGeom", new GeometryUDT())
            .add("length", DataTypes.DoubleType);

// using lambda function to register the UDF
sparkSession.udf().register("udf_bufferLength",
            (UDF2<Geometry, Double, Tuple2<Geometry, Double>>) (geom, distance) -> {
                Geometry buffed = geom.buffer(distance);
                Double length = buffed.getLength();
                return new Tuple2<>(buffed, length);
            },
            schemaUDF);

df.withColumn("bufferLength", functions.expr("udf_bufferLength(geom, distance)"))
            .select("geom", "distance", "bufferLength.*")
            .show();

from sedona.sql.types import GeometryType
from pyspark.sql.types import *

schemaUDF = StructType([
    StructField("buffed", GeometryType()),
    StructField("length", DoubleType())
])

def bufferAndLength(geom: GeometryType(), distance: DoubleType()):
    buffed = geom.buffer(distance)
    length = buffed.length
    return [buffed, length]

sedona.udf.register("udf_bufferLength", bufferAndLength, schemaUDF)

df.withColumn("bufferLength", expr("udf_bufferLength(geom, buffer)")) \
            .select("geom", "buffer", "bufferLength.*") \
            .show()

Output:

+------------------------------+--------+--------------------------------------------------+-----------------+
|                          geom|distance|                                        buffedGeom|           length|
+------------------------------+--------+--------------------------------------------------+-----------------+
|POLYGON ((1 1, 1 2, 2 1, 1 1))|    10.0|POLYGON ((1 -9, -0.9509032201612866 -8.80785280...|66.14518337329191|
+------------------------------+--------+--------------------------------------------------+-----------------+

Save to permanent storage

To save a Spatial DataFrame to some permanent storage such as Hive tables and HDFS, you can simply convert each geometry in the Geometry type column back to a plain String and save the plain DataFrame to wherever you want.

Use the following code to convert the Geometry column in a DataFrame back to a WKT string column:

SELECT ST_AsText(countyshape)
FROM polygondf

Save GeoJSON

Since v1.6.1, the GeoJSON data source in Sedona can be used to save a Spatial DataFrame to a single-line JSON file, with geometries written in GeoJSON format.

df.write.format("geojson").save("YOUR/PATH.json")

See this page for more information on writing to GeoJSON.

Save GeoParquet

Since v1.3.0, Sedona natively supports writing GeoParquet file. GeoParquet can be saved as follows:

df.write.format("geoparquet").save(geoparquetoutputlocation + "/GeoParquet_File_Name.parquet")

See this page for more information on writing to GeoParquet.

Save to Postgis

Unfortunately, the Spark SQL JDBC data source doesn't support creating geometry types in PostGIS using the 'createTableColumnTypes' option. Only the Spark built-in types are recognized. This means that you'll need to manage your PostGIS schema separately from Spark. One way to do this is to create the table with the correct geometry column before writing data to it with Spark. Alternatively, you can write your data to the table using Spark and then manually alter the column to be a geometry type afterward.

Postgis uses EWKB to serialize geometries. If you convert your geometries to EWKB format in Sedona you don't have to do any additional conversion in Postgis.

my_postgis_db# create table my_table (id int8, geom geometry);

df.withColumn("geom", expr("ST_AsEWKB(geom)")
    .write.format("jdbc")
    .option("truncate","true") // Don't let Spark recreate the table.
    // Other options.
    .save()

// If you didn't create the table before writing you can change the type afterward.
my_postgis_db# alter table my_table alter column geom type geometry;

Convert between DataFrame and SpatialRDD

DataFrame to SpatialRDD

Use SedonaSQL DataFrame-RDD Adapter to convert a DataFrame to an SpatialRDD.

var spatialRDD = StructuredAdapter.toSpatialRdd(spatialDf, "usacounty")

SpatialRDD spatialRDD = StructuredAdapter.toSpatialRdd(spatialDf, "usacounty")

from sedona.utils.structured_adapter import StructuredAdapter

spatialRDD = StructuredAdapter.toSpatialRdd(spatialDf, "usacounty")

"usacounty" is the name of the geometry column. It is an optional parameter. If you don't provide it, the first geometry column will be used.

SpatialRDD to DataFrame

Use SedonaSQL DataFrame-RDD Adapter to convert a DataFrame to an SpatialRDD. Please read Adapter Scaladoc

var spatialDf = StructuredAdapter.toDf(spatialRDD, sedona)

Dataset<Row> spatialDf = StructuredAdapter.toDf(spatialRDD, sedona)

from sedona.utils.adapter import StructuredAdapter

spatialDf = StructuredAdapter.toDf(spatialRDD, sedona)

SpatialRDD to DataFrame with spatial partitioning

By default, StructuredAdapter.toDf() does not preserve spatial partitions because doing so may introduce duplicate features for most types of spatial data. These duplicates are introduced on purpose to ensure correctness when performing a spatial join; however, when using Sedona to prepare a dataset for distribution this is not typically desired.

You can use StructuredAdapter and the spatialRDD.spatialPartitioningWithoutDuplicates function to obtain a Sedona DataFrame that is spatially partitioned without duplicates. This is especially useful for generating balanced GeoParquet files while preserving spatial proximity within files, which is crucial for optimizing filter pushdown performance in GeoParquet files.

spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE)
// Specify the desired number of partitions as 10, though the actual number may vary
// spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE, 10)
var spatialDf = StructuredAdapter.toSpatialPartitionedDf(spatialRDD, sedona)

spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE)
// Specify the desired number of partitions as 10, though the actual number may vary
// spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE, 10)
Dataset<Row> spatialDf = StructuredAdapter.toSpatialPartitionedDf(spatialRDD, sedona)

from sedona.utils.structured_adapter import StructuredAdapter

spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE)
# Specify the desired number of partitions as 10, though the actual number may vary
# spatialRDD.spatialPartitioningWithoutDuplicates(GridType.KDBTREE, 10)
spatialDf = StructuredAdapter.toSpatialPartitionedDf(spatialRDD, sedona)

SpatialPairRDD to DataFrame

PairRDD is the result of a spatial join query or distance join query. SedonaSQL DataFrame-RDD Adapter can convert the result to a DataFrame. But you need to provide the schema of the left and right RDDs.

var joinResultDf = StructuredAdapter.toDf(joinResultPairRDD, leftDf.schema, rightDf.schema, sedona)

Dataset joinResultDf = StructuredAdapter.toDf(joinResultPairRDD, leftDf.schema, rightDf.schema, sedona);

from sedona.utils.adapter import StructuredAdapter

joinResultDf = StructuredAdapter.pairRddToDf(result_pair_rdd, leftDf.schema, rightDf.schema, spark)