# Round Down (Spatial Analyst)

## Summary

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

## 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```
• There is a difference between the Int tool and the Round Down tool. For example, given the following two values, Int always truncates the number:

• 1.5 becomes 1
• -1.5 becomes -1

For the same two values, Round Down returns the following:

• 1.5 becomes 1.0
• -1.5 becomes -2.0

Another difference is that Round Down outputs floating-point values, while Int only outputs integer values.

• 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.

• See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.

## Syntax

`RoundDown(in_raster_or_constant)`
 Parameter 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.sa import *
env.workspace = "C:/sapyexamples/data"
outRoundDown.save("C:/sapyexamples/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 cell in a raster
# 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

# Execute RoundDown
outRoundDRaster = RoundDown(inRaster)

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

## Licensing information

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