Less Than Frequency (Spatial Analyst)

Summary

Evaluates on a cell-by-cell basis the number of times a set of rasters is less than another raster.

Illustration

 OutRas = LessThanFrequency(ValRas, [InRas1, InRas2, InRas3]

Usage

• An arbitrary number of rasters can be specified in the input rasters list.

• If a cell location contains NoData on any of the input rasters, that location will be assigned NoData on the output.

• The output raster is always of integer type.

Syntax

LessThanFrequency (in_value_raster, in_rasters)
 Parameter Explanation Data Type in_value_raster For each cell location in the input value raster, the number of occurrences (frequency) where a raster in the input list has a lesser value is counted. Raster Layer in_rasters[in_raster,...] The list of rasters that will be compared against the value raster. Raster Layer

Return Value

 Name Explanation Data Type out_raster The output raster. For each cell in the output raster, the value represents the number of times that the corresponding cells in the list of rasters is less than the value raster. Raster

Code Sample

LessThanFrequency example 1 (Python window)

This example evaluates the number of times a set of input GRID rasters is less than another raster and outputs the result as an IMG raster.

```import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outLTF = LessThanFrequency("cost", ["degs", "negs", "fourgrd"])
outLTF.save("C:/sapyexamples/output/outltf.img")```
LessThanFrequency example 2 (stand-alone script)

This example evaluates the number of times a set of input GRID rasters is less than another raster and outputs the result as an IMG raster.

```# Name: LessThanFrequency_Ex_02.py
# Description: Evaluates the number of times a set of rasters is
#              less than another raster
# Requirements: Spatial Analyst Extension
# Author: ESRI

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

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

# Set local variables
inValueRaster = "cost"
inRaster01 = "degs"
inRaster02 = "negs"
inRaster03 = "fourgrd"

# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")

# Execute LessThanFrequency
outLTF = LessThanFrequency(inValueRaster, [inRaster01, inRaster02, inRaster03])

# Save the output
outLTF.save("C:/sapyexamples/output/outltf")```

Licensing Information

ArcView: Requires Spatial Analyst
ArcEditor: Requires Spatial Analyst
ArcInfo: Requires Spatial Analyst

6/29/2011