Available with Spatial Analyst license.
Available with Image Analyst license.
Summary
Calculates the natural logarithm (base e) of cells in a raster.
Illustration
Usage
The input can be of integer or float type.
You can review some results for floating-point input values in the examples of output values from the Logarithmic tools.
Input values that are 0 or negative will be NoData in the output raster.
The output raster from this tool is always floating-point type, regardless of the input value type.
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.
The natural logarithm (Ln) is the most commonly used logarithmic function.
Syntax
Ln(in_raster_or_constant)
Parameter | Explanation | Data Type |
in_raster_or_constant | Input values for which to find the natural logarithm (Ln). 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 (natural) logarithm of the input values. | Raster |
Code sample
This example calculates the natural logarithm (base e) of the input raster values.
import arcpy
from arcpy import env
from arcpy.ia import *
env.workspace = "C:/iapyexamples/data"
outLn = Ln("elevation")
outLn.save("C:/iapyexamples/output/outln2")
This example calculates the natural logarithm (base e) of the input raster values.
# Name: Ln_Ex_02.py
# Description: Calculates natural logarithm (base e) of pixels 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 = "elevation"
# Check out the ArcGIS Image Analyst extension license
arcpy.CheckOutExtension("ImageAnalyst")
# Execute Ln
outLn = Ln(inRaster)
# Save the output
outLn.save("C:/iapyexamples/output/outln")
Environments
Licensing information
- Basic: Requires Image Analyst or Spatial Analyst
- Standard: Requires Image Analyst or Spatial Analyst
- Advanced: Requires Image Analyst or Spatial Analyst