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Reclassify

Available with Spatial Analyst license.

Available with 3D Analyst license.

Summary

Reclassifies (or changes) the values in a raster.

Usage

  • If a range of values is to be reclassed, the ranges should not overlap except at the boundary of two input ranges. Where overlapping occurs, the higher end of the lower input range is inclusive, and the lower end of the higher input range is exclusive.

    For example, if two ranges are specified, such as reclassifying values 1 to 5 as 100 and values 5 to 10 as 200, an input value less than or equal to 5 will be assigned the value 100 in the output, and an input value that is larger than 5, such as 5.01, will be assigned to 200.

  • From the tool, the remap table can be stored for future use with the Save option. You can save the remap to any relational table format. Use the Load option to reload remap tables you previously created with the Save button.

  • It is recommended to only load tables previously saved by the Reclassify tool. The table format is specific and must contain the fields FROM, TO, OUT, and MAPPING.

  • If the input raster has an attribute table, it will be used to create the initial reclassification table. If the input raster does not have an attribute table, you can run the Build Raster Attribute Table tool from the Data Management toolbox to build one before inputting the raster into the Reclassify tool. Otherwise, when you input the raster, a reclassification table will be created for it by first applying geoprocessing environment settings, such as Extent and Cell size, and scanning the raster.

    When the input raster is a layer from Contents, the default reclassification table will import the unique values or classified break values as specified by the layer symbology. The current geoprocessing environment settings will be ignored when importing those values. Otherwise, the reclassification must be manually entered or generated using the unique or classification options.

  • Once the remap table of the reclassification has been modified, the table will not be updated if a new input raster is selected. If the reclassification is not suitable for the new raster, a new reclassification can be reinitialized by one of the following methods

    • Remove all remap records using the erase option and manually add the new values.
    • Select the unique or classification options to generate a new reclassification.
  • When using the Reclassify tool as part of a model

    • If the input to the tool is derived data from a tool that isn't already run, the remap parameter in the Reclassify tool will be empty until the preceding tool is run and the model is validated. To avoid this, always run preceding tools before connecting their output variables as input to the Reclassify tool. Alternatively, you can create a custom reclassification table by adding entries.
    • If exposing the reclassification table as a model parameter, the reclass field must be exposed as a variable; however, it does not need to be set as a model parameter. If the field is not exposed as a variable, the classify and unique values buttons will be disabled in the model tool dialog box.
  • By default, this tool will take advantage of multi-core processors. The maximum number of cores that can be utilized is limited to four.

    If you want the tool to use fewer cores, use the parallelProcessingFactor environment setting.

Syntax

Reclassify_3d (in_raster, reclass_field, remap, out_raster, {missing_values})
ParameterExplanationData Type
in_raster

The input raster to be reclassified.

Raster Layer
reclass_field

Field denoting the values that will be reclassified.

Field
remap

A remap list that defines how the values will be reclassified.

The remap list is composed of three components: From, To, and New values. Each row in the remap list is separated by a semicolon, and the three components are separated by spaces. For example

"0 5 1;5.01 7.5 2;7.5 10 3"

Remap
out_raster

The output reclassified raster.

The output will always be of integer type.

Raster Dataset
missing_values
(Optional)

Denotes whether missing values in the reclass table retain their value or get mapped to NoData.

  • DATASignifies that if any cell location on the input raster contains a value that is not present or reclassed in a remap table, the value should remain intact and be written for that location to the output raster. This is the default.
  • NODATASignifies that if any cell location on the input raster contains a value that is not present or reclassed in a remap table, the value will be reclassed to NoData for that location on the output raster.
Boolean

Code sample

Reclassify example 1 (Python window)

The following example shows how to reclassify a raster into seven classes.

import arcpy
from arcpy import env  
env.workspace = "C:/sapyexamples/data"
arcpy.Reclassify_3d("C:/data/landuse", "VALUE", 
                    "1 9;2 8;3 1;4 6;5 3;6 2;7 1",
                    "C:/output/outremap","DATA")
Reclassify example 2 (stand-alone script)

This example reclassifies the input raster based on the values in a string field.

# Name: Reclassify_3d_Ex_02.py
# Description: Reclassifies the values in a raster.
# Requirements: 3D Analyst Extension

# Import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data"

# Set local variables
inRaster = "landuse"
field = "VALUE"
remapString = "1 9;2 8;3 1;4 6;5 3;6 2;7 1"
outRaster = "C:/output/reclass3d"

# Execute Reclassify
arcpy.Reclassify_3d(inRaster, field, remapString, outRaster, "DATA")

Licensing information

  • ArcGIS Desktop Basic: Requires 3D Analyst or Spatial Analyst
  • ArcGIS Desktop Standard: Requires 3D Analyst or Spatial Analyst
  • ArcGIS Desktop Advanced: Requires 3D Analyst or Spatial Analyst

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