projfwd

Forward map projection using PROJ.4 map projection library

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Syntax

[x,y] = projfwd(proj,lat,lon)

Description

example

[x,y] = projfwd(proj,lat,lon) returns the x and y map coordinates from the forward projection transformation. proj is a structure defining the map projection. proj can be an mstruct or a GeoTIFF info structure. lat and lon are arrays of the latitude and longitude coordinates.

For a complete list of GeoTIFF info and map projection structures that you can use with projinv, see the reference page for projlist.

Examples

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Open Live Script

Display the state boundary of Massachusetts over an orthophoto of Boston.

First, read geographic vector data for the state boundary of Massachusetts.

S = shaperead('usastatehi','UseGeoCoords',true, ...
    'Selector',{@(name) strcmpi(name,'Massachusetts'),'Name'});

Get projection information about the orthophoto using geotiffinfo. Then, project the state boundary vectors.

proj = geotiffinfo('boston.tif');
[x,y] = projfwd(proj,S.Lat,S.Lon);

Read and display the orthophoto image of Boston.

[A,R] = readgeoraster('boston.tif');
mapshow(A,R)
xlabel('MA Mainland State Plane easting, survey feet')
ylabel('MA Mainland State Plane northing, survey feet')

Display the state boundary. Show more detail by setting the map limits.

mapshow(x,y,'Color','k','LineWidth',2)
xlim([ 645000  895000]);
ylim([2865000 3040000]);

Input Arguments

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Map projection, specified as a scalar map projection structure (mstruct) or GeoTIFF info structure.

Data Types: struct

Geodetic latitudes of one or more points, specified as a scalar value, vector, matrix, or N-D array, in units of degrees. Size must match the size of the lon input.

Data Types: single | double

Longitudes of one or more points, specified as a scalar value, vector, matrix, or N-D array, in units of degrees. Size must match the size of the lat input.

Data Types: single | double

Output Arguments

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x-coordinates of one or more points in the projected coordinate system, returned as a scalar value, vector, matrix, or N-D array.

y-coordinates of one or more points in the projected coordinate system, returned as a scalar value, vector, matrix, or N-D array.

See Also

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Introduced before R2006a

Mapping Toolbox Documentation
Support