/** Create the WCS using the definition given in the FITS header. */
public WCS(Header h) throws TransformationException {
wcsKeys = new HashMap<String, Object>();
this.h = h;
headerNaxis = new int[2];
if (checkDSS()) {
headerNaxis[0] = h.getIntValue("NAXIS1");
headerNaxis[1] = h.getIntValue("NAXIS2");
if (headerNaxis[0] == 0) {
headerNaxis[0] = h.getIntValue("XPIXELS");
headerNaxis[1] = h.getIntValue("YPIXELS");
}
doDSSWCS();
stdWCS = false;
} else if (checkNeat()) {
headerNaxis[0] = h.getIntValue("NAXIS1");
headerNaxis[1] = h.getIntValue("NAXIS2");
doNeatWCS();
stdWCS = false;
} else { // More or less standard FITS WCS
getAxes();
if (lonAxis == -1 || latAxis == -1) {
throw new TransformationException("Unable to find coordinate axes");
}
headerNaxis[0] = h.getIntValue("NAXIS" + lonAxis);
headerNaxis[1] = h.getIntValue("NAXIS" + latAxis);
extractCoordinateSystem();
extractProjection();
extractScaler();
}
}
/**
* Find which axes are being used for coordinates. Normally this will just be 1 and 2, but
* occasionally we may be surprised.
*/
private void getAxes() {
int naxes = h.getIntValue("NAXIS");
// The first axes match are assumed to be correct.
for (int i = 1; i <= naxes; i += 1) {
String axis = h.getStringValue("CTYPE" + i);
if (axis != null && axis.length() >= 4) {
axis = axis.substring(0, 4);
} else {
continue;
}
if (lonAxis == -1) {
if (axis.equals("RA--")
|| axis.equals("GLON")
|| axis.equals("ELON")
|| axis.equals("HLON")) {
lonAxis = i;
}
}
if (latAxis == -1) {
if (axis.equals("DEC-")
|| axis.equals("GLAT")
|| axis.equals("ELAT")
|| axis.equals("HLAT")) {
latAxis = i;
}
}
}
if (lonAxis > -1) {
wcsKeys.put("CTYPE1", h.getStringValue("CTYPE" + lonAxis));
}
if (latAxis > -1) {
wcsKeys.put("CTYPE2", h.getStringValue("CTYPE" + latAxis));
}
}