Log2 (Spatial Analyst)
Summary
Calculates the base 2 logarithm of cells in a raster.
Illustration
 |
OutRas = Log2(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.
Syntax
| 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
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")
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
# 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 = "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")