# Exp (Spatial Analyst)

## Summary

Calculates the base e exponential of the cells in a raster.

## Illustration OutRas = Exp(InRas1)

## Usage

• Input values can be integer or float, and can be negative as well as positive.

See here for some examples of the outputs for floating point input values from the Exponential tools.

• The base e exponential is the most commonly used exponential function.

• Input values less than or equal to -745 will be set to NoData in the output, because these values cannot be accurately represented by 32-bit floating-point numbers.

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

• Output values from this tool are always positive.

## Syntax

Exp (in_raster_or_constant)
 Parameter Explanation Data Type in_raster_or_constant The input values for which to find the base e exponential. In order 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 base e exponential of the input values. Raster

## Code Sample

Exp example 1 (Python window)

This example calculates the base e exponential of the input raster values, and returns the result as a TIFF raster.

```import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outExp = Exp("landuse")
outExp.save("C:/sapyexamples/output/outexp.tif")```
Exp example 2 (stand-alone script)

This example calculates the base e exponential of the input raster values.

```# Name: Exp_Ex_02.py
# Description: Calculates the base e exponential of cells in a 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
inRaster = "landuse"

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

# Execute Exp
outExp = Exp(inRaster)

# Save the output
outExp.save("C:/sapyexamples/output/outexp")```

## Licensing Information

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

6/29/2011