Skip To Content

Less Than

Available with Spatial Analyst license.

Available with Image Analyst license.

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.

Learn more about how the Relational Math tools work

Illustration

Less Than (Relational) illustration
OutRas = LessThan(InRas1, 2)

Usage

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

  • The order of inputs is relevant for this tool.

  • 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.

Syntax

LessThan (in_raster_or_constant1, in_raster_or_constant2)
ParameterExplanationData 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 be able 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 be able to specify a number for both inputs, the cell size and extent must first be set in the environment.

Raster Layer; Constant

Return Value

NameExplanationData 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

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

Related topics