Available with Spatial Analyst license.
Summary
Extracts the cells of a raster that correspond to the areas defined by a mask.
Illustration
Usage
Additional attributes from the input raster, if any, will be carried over as-is to the output raster attribute table. Depending on the property being recorded, some of the attribute values may need to be recalculated.
When a multiband raster is specified as the Input Raster (in_raster in Python) value, all bands will be used.
To process a selection of bands from a multiband raster, first create a raster dataset composed of those particular bands using the Composite Bands tool. Then use the result as the Input Raster (in_raster in Python) value.
See AlsoHow to Clip a Raster to a Polygon or an Extent with Python (Extract by Mask) – OpenSourceOptionsWhat we know about the shooting of an Uber driver in Ohio and the scam surrounding itExtract by mask issueExtract by Mask - Resampling Options?The default output format is a geodatabase raster. If an Esri Grid stack is specified as the output format, the name of the stack cannot start with a number, use spaces, or be more than nine characters in length.
When a multiband raster is specified for the input raster mask, only the first band will be used in the operation.
When the Input raster (in_raster in Python) value and the Input raster or feature mask data raster data (in_mask_data in Python) are of the same cell size and the cells are aligned, they will be used directly in the tool. They will not be resampled internally during tool operation.
If the cell size is different, the output cell size will be the maximum of the inputs, and the Input raster value will be used as the snap raster internally. If the cell size is the same but the cells are not aligned, the Input raster value will be used as the snap raster internally. Either of these cases will trigger an internal resampling before the extraction operation is performed.
More information is available in the Cell Size and Snap Raster environment topics.
If the mask input is a feature, it will be converted to a raster internally, using the cell size and cell alignment (snap raster) from the Input raster value by default.
If Mask is specified in the environment setting while running the Extract by Mask tool, the output raster will have cell values only for the area that lies within the intersection of the environment mask and the input mask data.
You can use the Analysis Extent (analysis_extent in Python) parameter to specify the output analysis area explicitly for a stand-alone tool operation or to override the environment setting as part of a workflow. You can specify the extent by typing values, choosing the display extent, selecting a layer, or browsing for an input dataset.
The default Analysis Extent value is calculated from the intersection of the Input raster value and the Input raster or feature mask data value.
If the analysis extent is not explicitly specified as the parameter value, it will be derived from the analysis environment settings.
See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.
Parameters
Label | Explanation | Data Type |
Input raster | The input raster from which cells will be extracted. | Raster Layer |
Input raster or feature mask data | The input mask data defining the cell locations to extract. It can be a raster or a feature dataset. When the input mask data is a raster, NoData cells on the mask will be assigned NoData values on the output raster. When the input mask is feature data, cells in the input raster whose center falls within the specified shape of the feature will be included in the output, while cells whose center falls outside will receive NoData. | Raster Layer; Feature Layer |
Extraction Area (Optional) | Specifies whether cells inside or outside the locations defined by the input mask will be selected and written to the output raster.
| String |
Analysis Extent (Optional) | The extent that defines the area to be extracted. By default, the extent is calculated as the intersection of the Input raster value and the Input raster or feature mask data value. Processing will occur out to the x and y limits, and cells outside that extent will be NoData. The coordinates are specified in the same map units as the input raster if not explicitly set by the analysis environment.
| Extent |
Return Value
Label | Explanation | Data Type | Output raster | The output raster containing the cell values extracted from the input raster. | Raster |
ExtractByMask(in_raster, in_mask_data, {extraction_area}, {analysis_extent})
Name | Explanation | Data Type |
in_raster | The input raster from which cells will be extracted. | Raster Layer |
in_mask_data | The input mask data defining the cell locations to extract. It can be a raster or a feature dataset. When the input mask data is a raster, NoData cells on the mask will be assigned NoData values on the output raster. When the input mask is feature data, cells in the input raster whose center falls within the specified shape of the feature will be included in the output, while cells whose center falls outside will receive NoData. | Raster Layer; Feature Layer |
extraction_area (Optional) | Specifies whether cells inside or outside the locations defined by the input mask will be selected and written to the output raster.
| String |
analysis_extent (Optional) | The extent that defines the area to be extracted. If not specified, the default extent is the intersection of the in_raster value and the in_mask_data value. The coordinates are specified in the same map units as the input raster if not explicitly set by the analysis environment.
| Extent |
Return Value
Name | Explanation | Data Type | out_raster | The output raster containing the cell values extracted from the input raster. | Raster |
Code sample
This example extracts cells from a raster within a mask defined by an input polygon shapefile feature class.
import arcpyfrom arcpy import envfrom arcpy.sa import *env.workspace = "C:/sapyexamples/data"outExtractByMask = ExtractByMask("elevation", "mask.shp", "INSIDE")outExtractByMask.save("C:/sapyexamples/output/maskextract")
This example extracts cells from a raster for all areas outside a mask defined by an input polygon shapefile feature class, keeping the output extent of the input raster.
# Name: ExtractByMask_Ex_02.py# Description: Extracts the cells of a elevation raster for all areas outside of the mask features.# Keeping the output extent of the input elevation raster. # Requirements: Spatial Analyst Extension# Import system modulesimport arcpyfrom arcpy import envfrom arcpy.sa import *# Set environment settingsenv.workspace = "C:/sapyexamples/data"# Set local variablesinRaster = "elevation"inMaskData = "mask.shp"extraction_area = "OUTSIDE"analysis_extent = "elevation"# Execute ExtractByMaskoutExtractByMask = ExtractByMask(inRaster, inMaskData, extraction_area, analysis_extent)# Save the output outExtractByMask.save("C:/sapyexamples/output/extractmask")
Environments
Auto Commit, Cell Size, Cell Size Projection Method, Compression, Current Workspace, Extent, Geographic Transformations, Mask, Output CONFIG Keyword, Output Coordinate System, Scratch Workspace, Snap Raster, Tile Size
Licensing information
- Basic: Requires Spatial Analyst
- Standard: Requires Spatial Analyst
- Advanced: Requires Spatial Analyst
Related topics
- An overview of the Extraction toolset
- Find a geoprocessing tool
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