latlon2local

Convert geographic coordinates to local Cartesian coordinates

Description

example

[xEast,yNorth,zUp] = latlon2local(lat,lon,alt,origin) converts point locations given by lat, lon, and alt from geographic coordinates to local Cartesian coordinates returned as xEast, yNorth, and zUp. origin specifies the anchor of the local coordinate system as a vector of the form [latOrigin,lonOrigin,altOrigin]. Local x, y, z coordinates align with east, north and up directions, respectively. alt and altOrigin are altitudes as returned by a typical GPS sensor.

Examples

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Load a GPS route.

d = load('geoRoute.mat');

Define the origin in geographic coordinates, latitude and longitude.

alt = 10;  % 10 meters is an approximate altitude in Boston, MA
origin = [d.latitude(1), d.longitude(1), alt];

Convert the route from geographic coordinates to Cartesian coordinates, x and y.

[xEast,yNorth] = latlon2local(d.latitude,d.longitude,alt,origin);

Plot the route in Cartesian coordinates.

figure;
plot(xEast,yNorth)
axis('equal'); % set 1:1 aspect ratio to see real-world shape

Input Arguments

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Latitude coordinates, in degrees, specified as a numeric scalar or vector. Value must be in the range [–90, 90]. lat must be the same length as lon.

Example: lat = 42.3648

Data Types: single | double

Longitude coordinates, in degrees, specified as a numeric scalar or vector. Value must be in the range [–180, 180]. lon must be the same length as lat.

Example: lon = -71.0214

Data Types: single | double

Altitude, in meters, specified as a numeric scalar or vector.

Example: 10

Data Types: single | double

Anchor of local coordinate system, specified as a three-element vector of the form [latOrigin,lonOrigin,altOrigin].

Example: [42.3648, -71.0214, 10.0];

Data Types: single | double

Output Arguments

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x-coordinates, returned as a numeric scalar or vector, in meters.

xEast is the same class as lat. However, if any of the input arguments is of class single, then xEast is of class single.

y-coordinates, returned as a numeric scalar or vector, in meters.

yNorth is the same class as lon. However, if any of the input arguments is of class single, then yNorth is of class single.

Altitude, returned as a numeric scalar or vector, in meters.

zUp is the same class as alt. However, if any of the input arguments is of class single, then zUp is of class single.

Tips

  • The latitude and longitude of the geographic coordinate system use the WGS84 standard that is commonly used by GPS receivers.

  • This function defines altitude as the height, in meters, above the WGS84 reference ellipsoid.

  • Some GPS receivers use standards other than WGS84. Conversions using other ellipsoids are available in the Mapping Toolbox. This function addresses the most common conversion between geographic locations and Cartesian coordinates used by the on-board sensors of a vehicle.

Introduced in R2020a