/**
* Constructs an instance of a UTM coordinate transform with the supplied Ellipsoid, zone and
* hemisphere. The ellipsoid should be the one used as a basis for the UTM coordinates. The zone
* is the UTM zone which has positions to be converted; hemiflag is a boolean, true if points are
* northern hemisphere. You can convert points from more than one zone and hemisphere by using the
* method ConvertUtmToLatLon.
*
* <p>The reference coordinate system is RealTupleType.LatitudeLongitudeTuple; the incoming units
* are assumed to be UTM coords based on the input ellipsoid.
*
* <p>Most USGS topographic maps use the 1927 North American Datum (NAD 27); new maps are being
* slowly revised to NAD 83. To construct Ellipsoids for the first argument, import
* geotransform.jar, and do new CC_Ellipsoid() for NAD 27 (Clark 1866 ellipsoid), or new
* RF_Ellipsoid() for NAD 83 (GRS 80 ellipsoid), or new WE_Ellipsoid() for WSG 84. See
* http://www.ai.sri.com/geotransform/api.html for more details about 239 supported datums.
*
* @param ellipsoid the basis for some UTM coordinate system; many choices possible
* @param zone the UTM zone which has positions to be converted
* @param bounds Linear2DSet describing the bounds of this MapProjection
* @param hemiflag a boolean, true if points are in the northern hemisphere
* @throws VisADException
*/
public UTMCoordinateSystem(Ellipsoid ellipsoid, int zone, boolean hemiflag, Rectangle2D bounds)
throws VisADException {
super(RealTupleType.LatitudeLongitudeTuple, new Unit[] {CommonUnit.meter, CommonUnit.meter});
if (ellipsoid == null) {
throw new NullPointerException();
}
if ((zone < 1) || (zone > 60)) {
throw new IllegalArgumentException("UTM zone number not in range 1-60");
}
if (bounds != null) {
startX = bounds.getX();
startY = bounds.getY();
width = bounds.getWidth();
height = bounds.getHeight();
}
this.ellipsoid = ellipsoid;
this.onezone = zone;
this.onehemiflag = hemiflag;
// initialize the converters
Utm_To_Gdc_Converter.Init(ellipsoid);
Gdc_To_Utm_Converter.Init(ellipsoid);
}
/**
* Convert from lat/lon (GDC) coordinates to UTM coords. Note this finds UTM x/y and corresponding
* UTM zones (1...60) - use method getZoneNumbers(), and hemisphere flags == true if north - use
* method getHemisphereFlags(). All positions' elevations are set to zero.
*
* @param latlon lat/lon values (lat = latlon[0][i], lon=latlon[1][i])
* @return UTM coordinates (x = result[0][i], y=result[1][i])
* @throws VisADException unable to make transformation
*/
public float[][] fromReference(float[][] latlon) throws VisADException {
// initialize the coordinates in geotransform arrays
int MAX_POINTS = (latlon[0].length);
// set array sizes
zone = new int[MAX_POINTS];
hemisphere_north = new boolean[MAX_POINTS];
Gdc_Coord_3d gdc[] = new Gdc_Coord_3d[MAX_POINTS]; // these need to be the same len
Utm_Coord_3d utm[] = new Utm_Coord_3d[MAX_POINTS];
// move lat lon to right kind of object for geotransform menthods
// use cstr Gdc_Coord_3d( double lat, double lon, double elev )
for (int i = 0; i < MAX_POINTS; i++) {
gdc[i] = new Gdc_Coord_3d(latlon[0][i], latlon[1][i], 0.0);
utm[i] = new Utm_Coord_3d();
}
// convert the positions
Gdc_To_Utm_Converter.Convert(gdc, utm);
// switch utm coords back to double [][] array
float[][] result = new float[2][MAX_POINTS];
for (int i = 0; i < MAX_POINTS; i++) {
Utm_Coord_3d utmCoord = utm[i];
result[0][i] =
// TODO: Can we convert from one UTM zone to another?
// (float) ((utmCoord.zone - onezone)*10E6 + utmCoord.x);
(utmCoord.zone != onezone) ? Float.NaN : (float) utmCoord.x;
result[1][i] = (utmCoord.zone != onezone) ? Float.NaN : (float) utmCoord.y;
this.zone[i] = utmCoord.zone;
this.hemisphere_north[i] = utmCoord.hemisphere_north;
}
return result;
}
