minvtran

(To be removed) Unproject features from map to geographic coordinates

minvtran will be removed in a future release. In most cases, use the projinv function instead. If the mapprojection field of the current axesm-based map or specified map projection structure is 'globe', then use the ecef2geodetic function instead. For more information, see Version History.

Syntax

[lat,lon] = minvtran(x,y)
[lat,lon,alt] = minvtran(x,y,z)
[...] = minvtran(mstruct,...)

Description

[lat,lon] = minvtran(x,y) applies the inverse transformation defined by the map projection in the current axesm-based map. Using minvtran, you can convert point locations and line and polygon vertices in a planar, projected map coordinate system to latitudes and longitudes.

[lat,lon,alt] = minvtran(x,y,z) applies the inverse projection to 3-D input, resulting in 3-D output. If the input Z is empty or omitted, then Z = 0 is assumed.

[...] = minvtran(mstruct,...) takes a valid map projection structure as the first argument. In this case, no axesm-based map is needed.

Examples

Before using minvtran, it is necessary to create a map projection structure. You can do this with axesm or the defaultm function:

mstruct = defaultm('mercator');
mstruct.origin = [38.89 -77.04 0];
mstruct = defaultm(mstruct);

The following latitude and longitude data for the District of Columbia is obtained from the usastatelo shapefile:

dc = shaperead('usastatelo', 'UseGeoCoords', true,...
     'Selector',{@(name) strcmpi(name,'District of Columbia'),...
     'Name'});
lat = [dc.Lat]';
lon = [dc.Lon]';
[lat lon]

ans =

   38.9000  -77.0700
   38.9500  -77.1200
   39.0000  -77.0300
   38.9000  -76.9000
   38.7800  -77.0300
   38.8000  -77.0200
   38.8700  -77.0200
   38.9000  -77.0700
   38.9000  -77.0700
       NaN       NaN

This data can be projected into Cartesian coordinates of the Mercator projection using the projfwd function:

[x,y] = projfwd(mstruct,lat,lon);
[x y]
ans =

   -0.0004    0.5745
   -0.0011    0.5753
    0.0001    0.5762
    0.0019    0.5745
    0.0001    0.5724
    0.0003    0.5727
    0.0003    0.5739
   -0.0004    0.5745
   -0.0004    0.5745
       NaN       NaN

To transform the projected x-y data back into the unprojected geographic system, use the minvtran function: 

[lat2,lon2] = minvtran(mstruct,x,y);
[lat2 lon2]
ans =

   70.1302  -77.0987
   70.1729  -77.1969
   70.2157  -77.0204
   70.1300  -76.7659
   70.0276  -77.0205
   70.0447  -77.0010
   70.1046  -77.0009
   70.1302  -77.0987
   70.1302  -77.0987
       NaN       NaN

Version History

Introduced before R2006a

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See Also

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