map.geodesy.AuthalicLatitudeConverter

Convert between geodetic and authalic latitudes

Description

An AuthalicLatitudeConverter object provides conversion methods between geodetic and authalic latitudes for an ellipsoid with a given eccentricity.

The authalic latitude maps an ellipsoid (oblate spheroid) to a sphere while preserving surface area. Use authalic latitudes when implementing equal area map projections on the ellipsoid.

Creation

Syntax

converter = map.geodesy.AuthalicLatitudeConverter

converter = map.geodesy.AuthalicLatitudeConverter(spheroid)

Description

converter = map.geodesy.AuthalicLatitudeConverter creates an AuthalicLatitudeConverter object for a sphere and sets the Eccentricity to 0.

converter = map.geodesy.AuthalicLatitudeConverter(spheroid) creates an authalic latitude converter object and sets the Eccentricity property to match the specified spheroid object.

Input Arguments

spheroid — Reference spheroid

referenceEllipsoid object | oblateSpheroid object | referenceSphere object

Reference spheroid, specified as a referenceEllipsoid object, oblateSpheroid object, or referenceSphere object. The term reference spheroid is used synonymously with reference ellipsoid. To create a reference spheroid, use the creation function for the object. To specify the reference ellipsoid for WGS84, use the wgs84Ellipsoid function.

For more information about reference spheroids, see Comparison of Reference Spheroids.

Example: spheroid = referenceEllipsoid('GRS 80');

Properties

Eccentricity — Ellipsoid eccentricity

0 | numeric scalar

Ellipsoid eccentricity, specified as a numeric scalar. Eccentricity is in the interval [0, 0.5]. Eccentricities larger than 0.5 are possible in theory, but do not occur in practice and are not supported.

Data Types: double

Object Functions

forward	Convert geodetic latitude to authalic, conformal, isometric, or rectifying latitude
inverse	Convert authalic, conformal, isometric, or rectifying latitude to geodetic latitude

Examples

Create an Authalic Converter

Create a Geodetic Reference System 1980 (grs80) reference ellipsoid.

grs80 = referenceEllipsoid('GRS 80');

Create an authalic converter object and set the value of the Eccentricity property.

conv1 = map.geodesy.AuthalicLatitudeConverter;
conv1.Eccentricity = grs80.Eccentricity

conv1 = 

  AuthalicLatitudeConverter with properties:

    Eccentricity: 0.0818

Create an Authalic Converter Specifying a Spheroid

Create a reference ellipsoid.

grs80 = referenceEllipsoid('GRS 80');

Create an authalic latitude converter object based on the ellipsoid.

conv2 = map.geodesy.AuthalicLatitudeConverter(grs80)

conv1 = 

  AuthalicLatitudeConverter with properties:

    Eccentricity: 0.0818

Version History

Introduced in R2013a