Raster image manipulation

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Import Sedona¶

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from sedona.spark import *
from IPython.display import display, HTML
from sedona.spark import *
from IPython.display import display, HTML

Create a Sedona Context object.¶

If you already have a spark instance available, simply use SedonaContext.create(spark).

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config = SedonaContext.builder() .\
    config('spark.jars.packages',
           'org.apache.sedona:sedona-spark-3.4_2.12:1.5.1,'
           'org.datasyslab:geotools-wrapper:1.5.1-28.2,'
           'uk.co.gresearch.spark:spark-extension_2.12:2.11.0-3.4'). \
    config('spark.jars.repositories', 'https://artifacts.unidata.ucar.edu/repository/unidata-all'). \
    getOrCreate()

sedona = SedonaContext.create(config)

sc = sedona.sparkContext
config = SedonaContext.builder() .\
    config('spark.jars.packages',
           'org.apache.sedona:sedona-spark-3.4_2.12:1.5.1,'
           'org.datasyslab:geotools-wrapper:1.5.1-28.2,'
           'uk.co.gresearch.spark:spark-extension_2.12:2.11.0-3.4'). \
    config('spark.jars.repositories', 'https://artifacts.unidata.ucar.edu/repository/unidata-all'). \
    getOrCreate()

sedona = SedonaContext.create(config)

sc = sedona.sparkContext

https://artifacts.unidata.ucar.edu/repository/unidata-all added as a remote repository with the name: repo-1
Ivy Default Cache set to: /root/.ivy2/cache
The jars for the packages stored in: /root/.ivy2/jars
org.apache.sedona#sedona-spark-shaded-3.4_2.12 added as a dependency
org.datasyslab#geotools-wrapper added as a dependency
uk.co.gresearch.spark#spark-extension_2.12 added as a dependency
:: resolving dependencies :: org.apache.spark#spark-submit-parent-6230440f-ced2-4e0e-801e-6a29e7581b32;1.0
	confs: [default]
	found org.apache.sedona#sedona-spark-shaded-3.4_2.12;1.5.1 in central

:: loading settings :: url = jar:file:/opt/spark/jars/ivy-2.5.1.jar!/org/apache/ivy/core/settings/ivysettings.xml

	found edu.ucar#cdm-core;5.4.2 in repo-1
	found edu.ucar#udunits;5.4.2 in repo-1
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	found org.apache.httpcomponents#httpmime;4.5.13 in central
	found org.datasyslab#geotools-wrapper;1.5.1-28.2 in central
	found uk.co.gresearch.spark#spark-extension_2.12;2.11.0-3.4 in central
	found com.github.scopt#scopt_2.12;4.1.0 in central
downloading https://artifacts.unidata.ucar.edu/repository/unidata-all/edu/ucar/cdm-core/5.4.2/cdm-core-5.4.2.jar ...
	[SUCCESSFUL ] edu.ucar#cdm-core;5.4.2!cdm-core.jar (2448ms)
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downloading https://repo1.maven.org/maven2/joda-time/joda-time/2.10.3/joda-time-2.10.3.jar ...
	[SUCCESSFUL ] joda-time#joda-time;2.10.3!joda-time.jar (171ms)
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downloading https://repo1.maven.org/maven2/org/slf4j/slf4j-api/1.7.36/slf4j-api-1.7.36.jar ...
	[SUCCESSFUL ] org.slf4j#slf4j-api;1.7.36!slf4j-api.jar (87ms)
downloading https://repo1.maven.org/maven2/org/apache/httpcomponents/httpclient/4.5.13/httpclient-4.5.13.jar ...
	[SUCCESSFUL ] org.apache.httpcomponents#httpclient;4.5.13!httpclient.jar (190ms)
downloading https://repo1.maven.org/maven2/org/apache/httpcomponents/httpcore/4.4.13/httpcore-4.4.13.jar ...
	[SUCCESSFUL ] org.apache.httpcomponents#httpcore;4.4.13!httpcore.jar (131ms)
downloading https://repo1.maven.org/maven2/com/google/guava/failureaccess/1.0.1/failureaccess-1.0.1.jar ...
	[SUCCESSFUL ] com.google.guava#failureaccess;1.0.1!failureaccess.jar(bundle) (79ms)
downloading https://repo1.maven.org/maven2/com/google/guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar ...
	[SUCCESSFUL ] com.google.guava#listenablefuture;9999.0-empty-to-avoid-conflict-with-guava!listenablefuture.jar (106ms)
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	[SUCCESSFUL ] com.google.code.findbugs#jsr305;3.0.2!jsr305.jar (83ms)
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downloading https://repo1.maven.org/maven2/com/google/errorprone/error_prone_annotations/2.3.4/error_prone_annotations-2.3.4.jar ...
	[SUCCESSFUL ] com.google.errorprone#error_prone_annotations;2.3.4!error_prone_annotations.jar (87ms)
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downloading https://repo1.maven.org/maven2/commons-logging/commons-logging/1.2/commons-logging-1.2.jar ...
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	[SUCCESSFUL ] org.apache.httpcomponents#httpmime;4.5.13!httpmime.jar (81ms)
:: resolution report :: resolve 18063ms :: artifacts dl 6430ms
	:: modules in use:
	com.beust#jcommander;1.78 from central in [default]
	com.github.scopt#scopt_2.12;4.1.0 from central in [default]
	com.google.code.findbugs#jsr305;3.0.2 from central in [default]
	com.google.errorprone#error_prone_annotations;2.3.4 from central in [default]
	com.google.guava#failureaccess;1.0.1 from central in [default]
	com.google.guava#guava;30.1-jre from central in [default]
	com.google.guava#listenablefuture;9999.0-empty-to-avoid-conflict-with-guava from central in [default]
	com.google.j2objc#j2objc-annotations;1.3 from central in [default]
	com.google.protobuf#protobuf-java;3.12.4 from central in [default]
	com.google.re2j#re2j;1.3 from central in [default]
	commons-codec#commons-codec;1.11 from central in [default]
	commons-logging#commons-logging;1.2 from central in [default]
	edu.ucar#cdm-core;5.4.2 from repo-1 in [default]
	edu.ucar#httpservices;5.4.2 from repo-1 in [default]
	edu.ucar#udunits;5.4.2 from repo-1 in [default]
	joda-time#joda-time;2.10.3 from central in [default]
	org.apache.httpcomponents#httpclient;4.5.13 from central in [default]
	org.apache.httpcomponents#httpcore;4.4.13 from central in [default]
	org.apache.httpcomponents#httpmime;4.5.13 from central in [default]
	org.apache.sedona#sedona-spark-shaded-3.4_2.12;1.5.1 from central in [default]
	org.checkerframework#checker-qual;3.5.0 from central in [default]
	org.datasyslab#geotools-wrapper;1.5.1-28.2 from central in [default]
	org.jdom#jdom2;2.0.6 from central in [default]
	org.slf4j#slf4j-api;1.7.36 from central in [default]
	uk.co.gresearch.spark#spark-extension_2.12;2.11.0-3.4 from central in [default]
	---------------------------------------------------------------------
	|                  |            modules            ||   artifacts   |
	|       conf       | number| search|dwnlded|evicted|| number|dwnlded|
	---------------------------------------------------------------------
	|      default     |   25  |   21  |   21  |   0   ||   25  |   21  |
	---------------------------------------------------------------------
:: retrieving :: org.apache.spark#spark-submit-parent-6230440f-ced2-4e0e-801e-6a29e7581b32
	confs: [default]
	25 artifacts copied, 0 already retrieved (62899kB/105ms)
24/01/20 22:42:03 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
24/01/20 22:42:03 WARN Utils: Service 'SparkUI' could not bind on port 4040. Attempting port 4041.

Read GeoTiff files¶

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geotiff_df = sedona.read.format("binaryFile").load("data/raster/test5.tiff")
geotiff_df.show(2)
geotiff_df.createOrReplaceTempView("binary_raster")
geotiff_df = sedona.read.format("binaryFile").load("data/raster/test5.tiff")
geotiff_df.show(2)
geotiff_df.createOrReplaceTempView("binary_raster")

+--------------------+--------------------+------+--------------------+
|                path|    modificationTime|length|             content|
+--------------------+--------------------+------+--------------------+
|file:/opt/workspa...|2024-01-20 22:45:...|209199|[4D 4D 00 2A 00 0...|
+--------------------+--------------------+------+--------------------+

Create raster columns from the read binary data¶

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raster_df = sedona.sql("SELECT RS_FromGeoTiff(content) as raster from binary_raster")
raster_df.show(2)
raster_df.createOrReplaceTempView("raster_table")
raster_df = sedona.sql("SELECT RS_FromGeoTiff(content) as raster from binary_raster")
raster_df.show(2)
raster_df.createOrReplaceTempView("raster_table")

+--------------------+
|              raster|
+--------------------+
|GridCoverage2D["g...|
+--------------------+

Operate on rasters using Sedona¶

Once a raster column is created, you're now free to use the entire catalog of Sedona's raster functions. The following part of notebook contains a few examples.

Access raster metadata¶

RS_MetaData can be used to view the loaded raster's metadata (orientation and georeferencing attributes).

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raster_metadata = sedona.sql("SELECT RS_MetaData(raster) as metadata from raster_table")
metadata = raster_metadata.first()[0]
raster_srid = metadata[8]
metadata
raster_metadata = sedona.sql("SELECT RS_MetaData(raster) as metadata from raster_table")
metadata = raster_metadata.first()[0]
raster_srid = metadata[8]
metadata

Visualize rasters¶

Sedona 1.5.0 provides multiple ways to be able to visualize rasters. Throughout this notebook, RS_AsImage will be used to visualize any changes to the rasters.

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SedonaUtils.display_image(raster_df.selectExpr("RS_AsImage(raster, 500)"))
SedonaUtils.display_image(raster_df.selectExpr("RS_AsImage(raster, 500)"))

Join based on raster predicates¶

Sedona 1.5.0 now supports join predicates between raster and geometry columns.

Below is a simple example that carves a small rectangle from the existing raster and attempts to join it with the original raster

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(width, height) = sedona.sql("SELECT RS_Width(raster) as width, RS_Height(raster) as height from raster_table").first()
(p1X, p1Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {width / 2}, {height / 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {width / 2}, {height / 2}) as pY from raster_table").first()
(p2X, p2Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {(width / 2) + 2}, {height / 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {(width / 2) + 2}, {height / 2}) as pY from raster_table").first()
(p3X, p3Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {width / 2}, {(height / 2) + 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {width / 2}, {(height / 2) + 2}) as pY from raster_table").first()
(p4X, p4Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {(width / 2) + 2}, {(height / 2) + 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {(width / 2) + 2}, {(height / 2) + 2}) as pY from raster_table").first()
(width, height) = sedona.sql("SELECT RS_Width(raster) as width, RS_Height(raster) as height from raster_table").first()
(p1X, p1Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {width / 2}, {height / 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {width / 2}, {height / 2}) as pY from raster_table").first()
(p2X, p2Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {(width / 2) + 2}, {height / 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {(width / 2) + 2}, {height / 2}) as pY from raster_table").first()
(p3X, p3Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {width / 2}, {(height / 2) + 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {width / 2}, {(height / 2) + 2}) as pY from raster_table").first()
(p4X, p4Y) = sedona.sql(f"SELECT RS_RasterToWorldCoordX(raster, {(width / 2) + 2}, {(height / 2) + 2}) \
                  as pX, RS_RasterToWorldCoordY(raster, {(width / 2) + 2}, {(height / 2) + 2}) as pY from raster_table").first() 

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geom_wkt = f"SRID={int(raster_srid)};POLYGON (({p1X} {p1Y}, {p2X} {p2Y}, {p3X} {p3Y}, {p4X} {p4Y}, {p1X} {p1Y}))"
geom_wkt = f"SRID={int(raster_srid)};POLYGON (({p1X} {p1Y}, {p2X} {p2Y}, {p3X} {p3Y}, {p4X} {p4Y}, {p1X} {p1Y}))"

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geom_df = sedona.sql(f"SELECT ST_GeomFromEWKT('{geom_wkt}') as geom")
geom_df.createOrReplaceTempView("geom_table")
geom_df = sedona.sql(f"SELECT ST_GeomFromEWKT('{geom_wkt}') as geom")
geom_df.createOrReplaceTempView("geom_table")

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joined_df = sedona.sql("SELECT g.geom from raster_table r, geom_table g where RS_Intersects(r.raster, g.geom)")
joined_df.show()
joined_df = sedona.sql("SELECT g.geom from raster_table r, geom_table g where RS_Intersects(r.raster, g.geom)")
joined_df.show()

Interoperability between raster and vector data types¶

Sedona allows for conversions from raster to geometry and vice-versa.

Convert a raster to vector using convex hull¶

A convex hull geometry can be created out of a raster using RS_ConvexHull

Additionally, if a raster has noDataValue specified, and you wish to tighten the convexhull to exclude noDataValue boundaries, RS_MinConvexHull can be used.

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raster_convex_hull = sedona.sql("SELECT RS_ConvexHull(raster) as convex_hull from raster_table")
raster_min_convex_hull = sedona.sql("SELECT RS_MinConvexHull(raster) as min_convex_hull from raster_table")
raster_convex_hull.show(truncate=False)
raster_min_convex_hull.show(truncate=False)
raster_convex_hull = sedona.sql("SELECT RS_ConvexHull(raster) as convex_hull from raster_table")
raster_min_convex_hull = sedona.sql("SELECT RS_MinConvexHull(raster) as min_convex_hull from raster_table")
raster_convex_hull.show(truncate=False)
raster_min_convex_hull.show(truncate=False)

Convert a geometry to raster (Rasterize a geometry)¶

A geometry can be converted to a raster using RS_AsRaster

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rasterized_geom_df = sedona.sql("SELECT RS_AsRaster(ST_GeomFromWKT('POLYGON((150 150, 220 260, 190 300, 300 220, 150 150))'), r.raster, 'b', 230) as rasterized_geom from raster_table r")
rasterized_geom_df.show()
rasterized_geom_df = sedona.sql("SELECT RS_AsRaster(ST_GeomFromWKT('POLYGON((150 150, 220 260, 190 300, 300 220, 150 150))'), r.raster, 'b', 230) as rasterized_geom from raster_table r")
rasterized_geom_df.show()

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SedonaUtils.display_image(rasterized_geom_df.selectExpr("RS_AsImage(rasterized_geom, 250) as rasterized_geom"))
SedonaUtils.display_image(rasterized_geom_df.selectExpr("RS_AsImage(rasterized_geom, 250) as rasterized_geom"))

Perform Map Algebra operations¶

Sedona provides two ways to perform Map Algebra on rasters:

Using RS_MapAlgebra (preferred for simpler algebraic functions)
Using RS_BandAsArray and array based map algebra functions such as RS_Add, RS_Multiply (Useful for complex algebriac functions involving mutating each grid value differently.)

The following example illustrates how RS_MapAlgebra can be used. This example uses jiffle script to invert the colors of the above illustrated rasterized geometry.

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raster_white_bg = rasterized_geom_df.selectExpr("RS_MapAlgebra(rasterized_geom, NULL, 'out[0] = rast[0] == 0 ? 230 : 0;') as raster")
raster_white_bg = rasterized_geom_df.selectExpr("RS_MapAlgebra(rasterized_geom, NULL, 'out[0] = rast[0] == 0 ? 230 : 0;') as raster")

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SedonaUtils.display_image(raster_white_bg.selectExpr("RS_AsImage(raster, 250) as resampled_raster"))
SedonaUtils.display_image(raster_white_bg.selectExpr("RS_AsImage(raster, 250) as resampled_raster"))

Resample a raster.¶

Sedona 1.5.0 supports resampling a raster to different height/width or scale. It also supports changing the pivot of the raster.

Refer to RS_Resample documentation for more details.

This simple example changes the resolution of the loaded raster to 1000*1000

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resampled_raster_df = sedona.sql("SELECT RS_Resample(raster, 1000, 1000, false, 'NearestNeighbor') as resampled_raster from raster_table")
resampled_raster_df = sedona.sql("SELECT RS_Resample(raster, 1000, 1000, false, 'NearestNeighbor') as resampled_raster from raster_table")

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SedonaUtils.display_image(resampled_raster_df.selectExpr("RS_AsImage(resampled_raster, 500) as resampled_raster"))
SedonaUtils.display_image(resampled_raster_df.selectExpr("RS_AsImage(resampled_raster, 500) as resampled_raster"))

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resampled_raster_df.selectExpr("RS_MetaData(resampled_raster) as resampled_raster_metadata").show(truncate=False)
resampled_raster_df.selectExpr("RS_MetaData(resampled_raster) as resampled_raster_metadata").show(truncate=False)

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# Load another raster for some more examples
elevation_raster_df = sedona.read.format('binaryFile').load('data/raster/test1.tiff')
elevation_raster_df.createOrReplaceTempView("elevation_raster_binary")
# Load another raster for some more examples
elevation_raster_df = sedona.read.format('binaryFile').load('data/raster/test1.tiff')
elevation_raster_df.createOrReplaceTempView("elevation_raster_binary")

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elevation_raster_df = sedona.sql("SELECT RS_FromGeoTiff(content) as raster from elevation_raster_binary")
elevation_raster_df.createOrReplaceTempView("elevation_raster")
elevation_raster_df = sedona.sql("SELECT RS_FromGeoTiff(content) as raster from elevation_raster_binary")
elevation_raster_df.createOrReplaceTempView("elevation_raster")

Access individual values from rasters¶

Sedona provides RS_Value and RS_Values that allow accessing raster values at given geometrical point(s).

The following example extracts raster values at specific geographical points.

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point_wkt_1 = 'SRID=3857;POINT (-13095600.809482181 4021100.7487925636)'
point_wkt_2 = 'SRID=3857;POINT (-13095500.809482181 4021000.7487925636)'
point_df = sedona.sql("SELECT ST_GeomFromEWKT('{}') as point_1, ST_GeomFromEWKT('{}') as point_2".format(point_wkt_1, point_wkt_2))
point_df.createOrReplaceTempView("point_table")
test_df = sedona.sql("SELECT RS_Values(raster, Array(point_1, point_2)) as raster_values from elevation_raster, point_table")
test_df.show()
point_wkt_1 = 'SRID=3857;POINT (-13095600.809482181 4021100.7487925636)'
point_wkt_2 = 'SRID=3857;POINT (-13095500.809482181 4021000.7487925636)'
point_df = sedona.sql("SELECT ST_GeomFromEWKT('{}') as point_1, ST_GeomFromEWKT('{}') as point_2".format(point_wkt_1, point_wkt_2))
point_df.createOrReplaceTempView("point_table")
test_df = sedona.sql("SELECT RS_Values(raster, Array(point_1, point_2)) as raster_values from elevation_raster, point_table")
test_df.show()

Extract individual bands from rasters¶

RS_BandAsArray can be used to extract entire band values from a given raster

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band = elevation_raster_df.selectExpr("RS_BandAsArray(raster, 1)").first()[0]
print(band[500: 520],) #Print a part of a band as an array horizontally
band = elevation_raster_df.selectExpr("RS_BandAsArray(raster, 1)").first()[0]
print(band[500: 520],) #Print a part of a band as an array horizontally

Visualize Raster MBRs¶

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# Convert raster to its convex hull and transform it to EPSG:4326 to be able to visualize
raster_mbr_df = elevation_raster_df.selectExpr("ST_Transform(RS_ConvexHull(raster), 'EPSG:3857', 'EPSG:4326') as raster_mbr")
# Convert raster to its convex hull and transform it to EPSG:4326 to be able to visualize
raster_mbr_df = elevation_raster_df.selectExpr("ST_Transform(RS_ConvexHull(raster), 'EPSG:3857', 'EPSG:4326') as raster_mbr")

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sedona_kepler_map_elevation = SedonaKepler.create_map(df=raster_mbr_df, name='RasterMBR')
sedona_kepler_map_elevation
sedona_kepler_map_elevation = SedonaKepler.create_map(df=raster_mbr_df, name='RasterMBR')
sedona_kepler_map_elevation