ACos (Spatial Analyst)
Summary
Calculates the inverse cosine of cells in a raster.
Illustration
Usage
In mathematics, all Trigonometric functions have a defined range of valid input values, called the domain. The output values from each function also has a defined range. For this tool:
The Domain is : 1 ≤ [in_value] ≤ 1
Note that any input value that is outside this domain will receive NoData on the output raster.
The Range is : 0 ≤ [out_value] ≤ pi

The input values to ACos are interpreted as unitless.
Output values are always floating point, regardless of the input data type.
The output values from this tool are in radians. If degrees are desired, the resulting raster must be multiplied by the radianstodegrees conversion factor of 180/pi, or approximately 57.296.
See here for examples of converting output values from radians to degrees.
Syntax
Parameter  Explanation  Data Type 
in_raster_or_constant 
The input for which to calculate the inverse cosine values. 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 values are the inverse cosine of the input values.  Raster 
Code Sample
This example calculates the inverse cosine of the values in the input GRID raster and outputs a TIFF raster.
import arcpy from arcpy import env from arcpy.sa import * env.workspace = "C:/sapyexamples/data" outACos = ACos("degs") outACos.save("C:/sapyexamples/output/outacos.tif")
This example calculates the inverse cosine of the values in the input GRID raster.
# Name: ACos_Ex_02.py # Description: Calculates the inverse cosine 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 ACos outACos = ACos(inRaster) # Save the output outACos.save("C:/sapyexamples/output/outacos")