# ACosH (Spatial Analyst)

## Summary

Calculates the inverse hyperbolic cosine of cells in a raster.

## Illustration OutRas = ACosH(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] < ∞

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

• The Range is : -∞ < [out_value] < ∞

Note that here -∞ and ∞ represent the smallest negative and largest positive value supported by the particular raster format, respectively.

• The input and output values in ACosH are interpreted as unitless.

• Output values are always floating point, regardless of the input data type.

## Syntax

ACosH (in_raster_or_constant)
 Parameter Explanation Data Type in_raster_or_constant The input for which to calculate the inverse hyperbolic 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 hyperbolic cosine of the input values. Raster

## Code Sample

ACosH example 1 (Python window)

This example calculates the inverse hyperbolic cosine of the values in the input GRID raster and outputs an IMG raster.

```import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outACosH = ACosH("degs")
outACosH.save("C:/sapyexamples/output/outacosh.img")```
ACosH example 2 (stand-alone script)

This example calculates the inverse hyperbolic cosine of the values in the input GRID raster.

```# Name: ACosH_Ex_02.py
# Description: Calculates the inverse hyperbolic 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 ACosH
outACosH = ACosH(inRaster)

# Save the output
outACosH.save("C:/sapyexamples/output/outacosh")```

## Licensing Information

ArcView: Requires Spatial Analyst
ArcEditor: Requires Spatial Analyst
ArcInfo: Requires Spatial Analyst

6/29/2011