ACos (Image Analyst)

Available with Spatial Analyst license.

Available with Image Analyst license.

Summary

Calculates the inverse cosine of cells in a raster.

Illustration

ACos illustration
OutRas = ACos(InRas)

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 this tool 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. To use degrees instead, the resulting raster must be multiplied by the radians-to-degrees conversion factor of 180/pi, or approximately 57.296.

    For further assistance, a procedure to follow and examples of converting output in radians to degrees are available.

  • 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.

Syntax

ACos(in_raster_or_constant)
ParameterExplanationData Type
in_raster_or_constant

The input for which to calculate the inverse cosine values.

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

NameExplanationData Type
out_raster

The output raster.

The values are the inverse cosine of the input values.

Raster

Code sample

ACos example 1 (Python window)

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.ia import *
env.workspace = "C:/iapyexamples/data"
outACos = ACos("degs")
outACos.save("C:/iapyexamples/output/outacos.tif")
ACos example 2 (stand-alone script)

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 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 = "degs"

# Check out the ArcGIS Image Analyst extension license
arcpy.CheckOutExtension("ImageAnalyst")

# Execute ACos
outACos = ACos(inRaster)

# Save the output 
outACos.save("C:/iapyexamples/output/outacos")

Licensing information

  • Basic: Requires Image Analyst or Spatial Analyst
  • Standard: Requires Image Analyst or Spatial Analyst
  • Advanced: Requires Image Analyst or Spatial Analyst

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