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Apply a map algebra script on a raster. RS_MapAlgebra

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Signatures

RS_MapAlgebra (raster: Raster, pixelType: String, script: String)

RS_MapAlgebra (raster: Raster, pixelType: String, script: String, noDataValue: Double)

RS_MapAlgebra(rast0: Raster, rast1: Raster, pixelType: String, script: String, noDataValue: Double)

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Parameters

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rast0
Raster
The rast0 value.
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rast1
Raster
The rast1 value.
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pixelType
String
required
The pixel type value.
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script
String
required
The script value.
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noDataValue
Double
The NoData value to use for pixels outside the raster extent.
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raster
Raster
The input raster.

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Return type

The resulting raster.

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Examples

Calculate the NDVI of a raster with 4 bands (R, G, B, NIR): 
-- Assume that the input raster has 4 bands: R, G, B, NIR
-- rast[0] refers to the R band, rast[3] refers to the NIR band.
SELECT RS_MapAlgebra(rast, 'D', 'out = (rast[3] - rast[0]) / (rast[3] + rast[0]);') AS ndvi FROM raster_table

+--------------------+
|              raster|
+--------------------+
|GridCoverage2D["g...|
+--------------------+
Spark SQL Example for two raster input RS_MapAlgebra: 
RS_MapAlgebra(rast0, rast1, 'D', 'out = rast0[0] * 0.5 + rast1[0] * 0.5;', null)
For more details and examples about RS_MapAlgebra, please refer to the Map Algebra documentation. To learn how to write map algebra script, please refer to Jiffle language summary.