Ln (Spatial Analyst)
Summary
Calculates the natural logarithm (base e) of cells in a raster.
Illustration
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OutRas = Ln(InRas1) |
Usage
The input can be of integer or float type. See here for some examples of the outputs for floating point input 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.
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The natural logarithm (Ln) is the most commonly used logarithmic function.
Syntax
| Parameter | Explanation | Data Type |
in_raster_or_constant |
Input values for which to find the natural logarithm (Ln). 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 (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.sa import *
env.workspace = "C:/sapyexamples/data"
outLn = Ln("elevation")
outLn.save("C:/sapyexamples/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 cells 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
inRaster = "elevation"
# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")
# Execute Ln
outLn = Ln(inRaster)
# Save the output
outLn.save("C:/sapyexamples/output/outln")