Available with Spatial Analyst license.
Summary
Calculates the base 2 logarithm of cells in a raster.
Illustration
Usage
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.
See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.
Syntax
Log2 (in_raster_or_constant)
| Parameter | Explanation | Data Type |
in_raster_or_constant | Input values for which to find the base 2 logarithm. 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 2 logarithm of the input values. | Raster |
Code Sample
Log2 example (Python window)
This example calculates base 2 logarithm of the input raster values and generates the output as an IMG raster.
import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outLog2 = Log2("elevation")
outLog2.save("C:/sapyexamples/output/outlog2.img")
Log2 example 2 (stand-alone script)
This example calculates base 2 logarithm of the input raster values.
# Name: Log2_Ex_02.py
# Description: Calculates the base 2 logarithm 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 = "degs"
# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")
# Execute Log2
outLog2 = Log2(inRaster)
# Save the output
outLog2.save("C:/sapyexamples/output/outlog2")
Environments
Licensing Information
- ArcGIS for Desktop Basic: Requires Spatial Analyst
- ArcGIS for Desktop Standard: Requires Spatial Analyst
- ArcGIS for Desktop Advanced: Requires Spatial Analyst