# geoidegm96

Calculate geoid height as determined from EGM96 Geopotential Model

## Syntax

``N = geoidegm96(latitude,longitude)``
``N = geoidegm96(latitude,longitude,action)``

## Description

example

````N = geoidegm96(latitude,longitude)` calculates the geoid height as determined from the EGM96 Geopotential Model. This function interpolates geoid heights from a 15-minute grid of point values in the tide-free system, using the EGM96 Geopotential Model to the degree and order 360. The geoid undulations are relative to the WGS84 ellipsoid.`N = geoidegm96(latitude,longitude,action)` performs `action` if latitude `latitude` or longitude `longitude` are out of range.```

## Examples

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Calculate the geoid height at 42.4 degrees N latitude and 71.0 degrees E longitude

`N = geoidegm96( 42.4, 71.0)`
```N = -36.5900```

Calculate the geoid height at two different locations, with out-of-range actions generating warnings.

`N = geoidegm96( [39.3,33.4], [-77.2, 36.5])`
```N = -33.0100 25.5500```

Calculate the geoid height with latitude wrapping, with out-of-range actions displaying no warnings.

`N = geoidegm96(100,150,'None')`
```N = 36.4100```

## Input Arguments

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Geocentric latitudes, specified as an array of m values in degrees, where north latitude is positive and south latitude is negative. If `lat` is not within the range -90 to 90, inclusive, this function wraps the value to be within the range.

Data Types: `double` | `single`

Geocentric longitudes, specified as an array of m values in degrees, where east longitude is positive and west longitude is negative. If `long` is not within the range 0 to 360 inclusive, this function wraps the value to be within the range.

Data Types: `double` | `single`

Action for out-of-range input, specified as:

• `'Error'` — Displays warning and indicates that the input is out of range

• `'Warning'` — Displays error and indicates that the input is out of range

• `'None'` — Does not display warning or error

Data Types: `char` | `string`

## Output Arguments

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Geoid height, returned as an array in meters. The function calculates geoid heights to 0.01 meters.

 NIMA TR8350.2: "Department of Defense World Geodetic System 1984, Its Definition and Relationship with Local Geodetic Systems."

 NASA/TP-1998-206861: "The Development of the Joint NASA GSFC and NIMA Geopotential Model EGM96."