Does anyone know of a way, in Java, to convert an earth surface position from lat, lon to UTM (say in WGS84)? I'm currently looking at Geotools but unfortunately the solution is not obvious.

解决方案

I was able to use Geotools 2.4 to get something that works, based on some example code.

double utmZoneCenterLongitude = ... // Center lon of zone, example: zone 10 = -123

int zoneNumber = ... // zone number, example: 10

double latitude, longitude = ... // lat, lon in degrees

MathTransformFactory mtFactory = ReferencingFactoryFinder.getMathTransformFactory(null);

ReferencingFactoryContainer factories = new ReferencingFactoryContainer(null);

GeographicCRS geoCRS = org.geotools.referencing.crs.DefaultGeographicCRS.WGS84;

CartesianCS cartCS = org.geotools.referencing.cs.DefaultCartesianCS.GENERIC_2D;

ParameterValueGroup parameters = mtFactory.getDefaultParameters("Transverse_Mercator");

parameters.parameter("central_meridian").setValue(utmZoneCenterLongitude);

parameters.parameter("latitude_of_origin").setValue(0.0);

parameters.parameter("scale_factor").setValue(0.9996);

parameters.parameter("false_easting").setValue(500000.0);

parameters.parameter("false_northing").setValue(0.0);

Map properties = Collections.singletonMap("name", "WGS 84 / UTM Zone " + zoneNumber);

ProjectedCRS projCRS = factories.createProjectedCRS(properties, geoCRS, null, parameters, cartCS);

MathTransform transform = CRS.findMathTransform(geoCRS, projCRS);

double[] dest = new double[2];

transform.transform(new double[] {longitude, latitude}, 0, dest, 0, 1);

int easting = (int)Math.round(dest[0]);

int northing = (int)Math.round(dest[1]);