Less Than (Spatial Analyst)

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

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.

• 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, or one of the inputs is a constant, the output will be a multiband raster. The number of bands in each multiband input must be the same.

• The tool will perform the operation on each band from one input against the corresponding band from the other input. If one of the inputs is a multiband raster and the other input is a constant, the tool will perform the operation against the constant value for each band in the multiband input.

• 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)

Parameter	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")

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