Round Down (Image Analyst)

Available with Spatial Analyst license.

Summary

Returns the next lower integer value, just represented as a floating point, for each cell in a raster.

Illustration

OutRas = RoundDown(InRas1)

Usage

• Input values can be positive or negative.

• The output raster from this tool is always floating-point type, regardless of the input value type.

• If the input number has any values to the right of the decimal point, the output will be assigned the next lower integer value, but will be represented as a floating point number with no decimal portion. For example:

      Input   Output
       5.3     5.0
       4.9     4.0
       3.0     3.0
       6.5     6.0
      -0.2    -1.0
      -2.8    -3.0

• If the input is a multiband raster, the output will be a multiband raster. The tool will perform the operation on each band in the input.

• If the input is multidimensional raster data, all slices from all variables will be processed. The output will be a multidimensional raster in CRF format.

Parameters

Dialog

Label	Explanation	Data Type
Input raster or constant value	The input values to be rounded down. To use a number as an input for this parameter, 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 cell values are the result of rounding down the input values.	Raster

Python

RoundDown(in_raster_or_constant)

Name	Explanation	Data Type
in_raster_or_constant	The input values to be rounded down. To use a number as an input for this parameter, 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 cell values are the result of rounding down the input values.	Raster

Code sample

RoundDown example 1 (Python window)

This example rounds the values in the input raster to the next lower integer value and outputs a floating-point raster.

import arcpy
from arcpy import env
from arcpy.ia import *
env.workspace = "C:/iapyexamples/data"
outRoundDown = RoundDown("gwhead")
outRoundDown.save("C:/iapyexamples/output/outrd")

RoundDown example 2 (stand-alone script)

This example rounds the values in the input raster to the next lower integer value and outputs a floating-point raster.

# Name: RoundDown_Ex_02.py
# Description: Returns the next lower whole number for each pixel in a raster
# Requirements: Image Analyst Extension

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

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

# Set local variables
inRaster = "gwhead"

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

# Execute RoundDown
outRoundDRaster = RoundDown(inRaster)

# Save the output 
outRoundDRaster.save("C:/iapyexamples/output/outrounddown")

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Current Workspace, Extent, Geographic Transformations, Mask, Output CONFIG Keyword, Output Coordinate System, Scratch Workspace, Snap Raster, Tile Size