Less Than (Spatial Analyst)

Summary

Performs a Relational less-than operation on two inputs on a cell-by-cell basis.

Returns 1 for cells where the first raster is less than the second raster and 0 if it is not.

Usage

• Two inputs are necessary for this relational evaluation to take place.

• The order of inputs is relevant for this tool.

• If both inputs are single band rasters or one of the inputs is a constant, the output will be a single band raster.

• If both inputs are multiband rasters, the tool will perform the operation on each band from one input, and the output will be a multiband raster. The number of bands in each multiband input must be the same.

• If one of the inputs is a multiband raster and the other input is a constant, the tool will perform the operation using the constant value for each band in the multiband input, and the output will be a multiband raster.

• In ArcPy, if both inputs are multidimensional rasters with the same number of variables, the tool will perform the operation for all slices with the same dimension value, and the output will be a multidimensional raster. The variables in the inputs must have the same dimensions or common dimension but no uncommon dimensions.

If both inputs have one variable but different names, set the matchMultidimensionalVariable geoprocessing environment to False to perform the operation.

In ArcPy, if one of the inputs is a multidimensional raster and the other input is a constant, the tool will perform the operation for all slices for all variables using the constant value, and the output will be a multidimensional raster.

• In Map Algebra, the equivalent operator symbol for this tool is "<" (link).

• 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 or constant value 1 The input being tested to determine if it is less than the second input.A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. Raster Layer; Constant Input raster or constant value 2 The input against which the first input is tested to be less than.A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. Raster Layer; Constant

Return Value

 Label Explanation Data Type Output raster The output raster.The output cell values will be either integer 0 or 1, or NoData if any input cell value is NoData. Raster

`LessThan(in_raster_or_constant1, in_raster_or_constant2)`
 Name Explanation Data Type in_raster_or_constant1 The input being tested to determine if it is less than the second input.A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. Raster Layer; Constant in_raster_or_constant2 The input against which the first input is tested to be less than.A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. Raster Layer; Constant

Return Value

 Name Explanation Data Type out_raster The output raster.The output cell values will be either integer 0 or 1, or NoData if any input cell value is NoData. Raster

Code sample

LessThan example 1 (Python window)

This example performs a Relational less-than operation on two Grid rasters and outputs the result as a TIFF raster.

``````import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outLessThan = LessThan("degs", "negs")
outLessThan.save("C:/sapyexamples/output/outlt.tif")``````
LessThan example 2 (stand-alone script)

This example performs a Relational less-than operation on two Grid rasters.

``````# Name: LessThan_Ex_02.py
# Description: Performs a relational less-than operation on two inputs
#              on a cell-by-cell basis within the Analysis window
# Requirements: Spatial Analyst Extension

# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *

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

# Set local variables
inRaster1 = "degs"
inRaster2 = "negs"

# Execute LessThan
outLessThan = LessThan(inRaster1, inRaster2)

# Save the output
outLessThan.save("C:/sapyexamples/output/outlt")``````

Licensing information

• Basic: Requires Spatial Analyst or Image Analyst
• Standard: Requires Spatial Analyst or Image Analyst
• Advanced: Requires Spatial Analyst or Image Analyst