Skip to main content

ACos function

Available with Image Analyst license.

Available with Spatial Analyst license.

Overview

Calculates the inverse cosine of the pixels in a raster.

ACos illustration

Notes

In mathematics, all trigonometric functions have a defined range of valid input values, called the domain. The output values from each function also have a defined range. For this tool, the domain and range are as follows:

  • Domain: -1 ≤ [in_value] ≤ 1

  • Range: 0 ≤ [out_value] ≤ pi

Note that any input value that is outside this domain will receive NoData on the output raster.

The input values to this tool are in radians. If degrees are desired, the resulting raster must be multiplied by the radians-to-degrees conversion factor of 180/\(\pi\), or approximately 57.296.

The output raster is always a floating-point type, regardless of the input value type.

The output values from this tool are interpreted as unitless.

If the input is a multiband raster, the output will be a multiband raster. The function will perform the operation on each band in the input.

If the input is a multidimensional raster, all slices from all variables will be processed, and the output will be a multidimensional raster.

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

Parameters

Parameter name

Description

Raster

The input for which to calculate the inverse cosine values.

Extent Type

Choose which extent should be used in the output raster:

  • First Of—Use the extent of the first input raster to determine the processing extent.

  • Intersection Of—Use the extent of the overlapping pixels to determine the processing extent. This is the default.

  • Union Of—Use the extent of all the rasters to determine the processing extent.

  • Last Of—Use the extent of the last input raster to determine the processing extent.

Cellsize Type

Choose which cell size to use in the output raster. If all the input cell sizes are the same, all the options will yield the same results.

  • First Of—Use the first cell size of the input rasters.

  • Min Of—Use the smallest cell size of all the input rasters.

  • Max Of—Use the largest cell size of all the input rasters. This is the default.

  • Mean Of—Use the mean cell size of all the input rasters.

  • Last Of—Use the last cell size of the input rasters.