StdDev

Summary

Creates a raster object where each pixel contains the standard deviation value across multiple rasters.

Discussion

The referenced raster dataset for the raster object is temporary. To make it permanent, you can call the raster object's save method.

Syntax

StdDev (rasters, {extent_type}, {cellsize_type}, {ignore_nodata}, {process_as_multiband})

Parameter	Explanation	Data Type
rasters [rasters,...]	The list of input rasters.	Raster
extent_type	The method that will be used to compute the extent of the output when the input rasters have different extents. FirstOf—The output extent is defined using the extent of the first input raster. LastOf—The output extent is defined using the extent of the last input raster. IntersectionOf—The output extent is defined as the intersecting area of the input rasters. UnionOf—The output extent is defined as the total extent of the input rasters. (The default value is FirstOf)	String
cellsize_type	The method that will be used to compute the pixel size of the output when the input rasters have different pixel sizes. FirstOf—The output pixel size is defined using the pixel size of the first input raster. LastOf—The output pixel size is defined using the pixel size of the last input raster. MaxOf—The output pixel size is defined using the maximum pixel size of the input rasters. MeanOf—The output pixel size is defined using the mean of both input rasters. MinOf—The output pixel size is defined using the minimum pixel size of the input rasters. (The default value is FirstOf)	String
ignore_nodata	Specifies whether to ignore NoData values in the calculation. True—The analysis will include all valid pixels in the input rasters and ignore any NoData pixels. False—The analysis will result in NoData if there are any NoData values for the pixels in the input rasters. (The default value is False)	Boolean
process_as_multiband	Specifies how the bands of the input rasters are processed. True—Each multiband raster will be processed as a multiband raster. The operation will be performed for each band from one input using the corresponding band number from other inputs. False—Each band from a multiband raster input will be processed separately as a single-band raster. (The default value is False)	Boolean

Return Value

Data Type	Explanation
Raster	The output raster.

Code sample

StdDev example

Calculates the standard deviation across three multiband rasters.

from arcpy.ia import * 

rc = RasterCollection([landsat_1, landsat_2, landsat_3]) 

range_raster = StdDev(rc, extent_type = "UnionOf", cellsize_type = "MinOf", 
	ignore_nodata = True, process_as_multiband = True)