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Work in UTM Without a Displayed Map

You can set up UTM to calculate coordinates without generating a map display, using the defaultm function. The utmzone and utmgeoid functions help you select a zone and an appropriate ellipsoid. In this example, you generate UTM coordinate data for a location in New York City, using that point to define the projection itself.

Define a location in New York City. Obtain the UTM zone for this point.

lat = 40.7;
lon = -74.0;
z = utmzone(lat,lon)
z = 
'18T'

Get the suggested ellipsoid vector and name for this zone.

[ellipsoid,estr] = utmgeoid(z)
ellipsoid = 1×2
106 ×

    6.3782    0.0000

estr = 
'clarke66'

Set up the UTM coordinate system based on this information.

utmstruct = defaultm('utm');
utmstruct.zone = z;
utmstruct.geoid = ellipsoid;
utmstruct = defaultm(utmstruct);

Transform the coordinates, without a map display.

[x,y] = projfwd(utmstruct,lat,lon)
x = 5.8448e+05
y = 4.5057e+06

Compute the zone limits (latitude and longitude limits) for a specified zone by using the utmzone function. You can also call utmzone recursively to obtain the limits of the UTM zone within which a point location falls.

utmzone('18T')
ans = 1×4

    40    48   -78   -72

[zonelats,zonelons] = utmzone(utmzone(40.7,-74.0))
zonelats = 1×2

    40    48

zonelons = 1×2

   -78   -72

Alternatively, set up a UTM coordinate system using a projcrs object. To create the object, specify an EPSG code. For information about EPSG codes, see http://www.epsg.org/. Verify that the projcrs object has the correct name and ellipsoid. Then, transform the coordinates.

p = projcrs(26718);
p.Name
ans = 
"NAD27 / UTM zone 18N"
p.GeographicCRS.Spheroid.Name
ans = 
'Clarke 1866'
[xp,yp] = projfwd(p,lat,lon)
xp = 5.8448e+05
yp = 4.5057e+06

See Also

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