/**
* I have no idea what this does.
*
* @param grid sampling grid
* @param index some sort of index
* @return a new flat field with something different
* @throws RemoteException Java RMI error
* @throws VisADException VisAD error
*/
private static FlatField hatFieldOld(Set grid, int index) throws VisADException, RemoteException {
CoordinateSystem cs = grid.getCoordinateSystem();
boolean hasCS = (cs != null);
RealTupleType rtt = (hasCS) ? cs.getReference() : ((SetType) grid.getType()).getDomain();
int latI = rtt.getIndex(RealType.Latitude);
if (latI == -1) {
throw new IllegalArgumentException(grid.toString());
}
int lonI = rtt.getIndex(RealType.Longitude);
if (lonI == -1) {
throw new IllegalArgumentException(grid.toString());
}
if (grid.getManifoldDimension() < 2) {
throw new IllegalArgumentException(grid.toString());
}
int[][] neighbors = grid.getNeighbors(index);
LatLonPointImpl refPt = new LatLonPointImpl();
LatLonPointImpl neiPt = new LatLonPointImpl();
Bearing bearing = new Bearing();
float[] hat1 = new float[2];
float[] hat2 = new float[2];
float[][] hat = new float[2][grid.getLength()];
for (int i = 0; i < neighbors.length; i++) {
float[][] refCoords = grid.indexToValue(new int[] {i});
if (hasCS) {
refCoords = cs.toReference(refCoords);
}
float[][] neiCoords = grid.indexToValue(neighbors[i]);
if (hasCS) {
neiCoords = cs.toReference(neiCoords);
}
refPt.set(refCoords[latI][0], refCoords[lonI][0]);
compute(refPt, neiPt, neiCoords[latI][0], neiCoords[lonI][0], -180, bearing, hat1);
float d1 = (float) bearing.getDistance();
compute(refPt, neiPt, neiCoords[latI][1], neiCoords[lonI][1], 0, bearing, hat2);
float d2 = (float) bearing.getDistance();
boolean bad1 = Double.isNaN(d1);
boolean bad2 = Double.isNaN(d2);
if (bad1 && bad2) {
hat[0][i] = Float.NaN;
hat[1][i] = Float.NaN;
} else {
if (bad1) {
hat[0][i] = hat2[0];
hat[1][i] = hat2[1];
} else if (bad2) {
hat[0][i] = hat1[0];
hat[1][i] = hat1[1];
} else {
float tot = d1 + d2;
float c1 = d2 / tot;
float c2 = d1 / tot;
float xhat = c1 * hat1[0] + c2 * hat2[0];
float yhat = c1 * hat1[1] + c2 * hat2[1];
float mag = (float) Math.sqrt(xhat * xhat + yhat * yhat);
hat[0][i] = xhat / mag;
hat[1][i] = yhat / mag;
}
}
}
FlatField hatField =
new FlatField(
new FunctionType(
((SetType) grid.getType()).getDomain(),
new RealTupleType(
RealType.getRealType("xHat", CommonUnit.dimensionless),
RealType.getRealType("yHat", CommonUnit.dimensionless))),
grid);
hatField.setSamples(hat, false);
return hatField;
}
/**
* The returned {@link visad.FlatField} will have NaN-s for those unit vector components that
* could not be computed.
*
* @param grid The spatial grid.
* @param index The index of the manifold dimension along which to compute the unit vector.
* @return A field of components of the unit vector for the given manifold dimension.
* @throws NullPointerException if the grid is <code>null</code>.
* @throws IllegalArgumentException if the manifold dimension of the grid is less than 2 or if the
* grid doesn't contain {@link visad.RealType#Latitude} and {@link visad.RealType#Longitude}.
* @throws VisADException if a VisAD failure occurs.
* @throws RemoteException if a Java RMI failure occurs.
*/
private static FlatField hatFieldNew(Set grid, int index) throws VisADException, RemoteException {
CoordinateSystem cs = grid.getCoordinateSystem();
boolean hasCS = cs != null;
RealTupleType rtt = (hasCS) ? cs.getReference() : ((SetType) grid.getType()).getDomain();
int latI = rtt.getIndex(RealType.Latitude);
if (latI == -1) {
throw new IllegalArgumentException(rtt.toString());
}
int lonI = rtt.getIndex(RealType.Longitude);
if (lonI == -1) {
throw new IllegalArgumentException(rtt.toString());
}
if (grid.getManifoldDimension() < 2) {
throw new IllegalArgumentException(grid.toString());
}
int[][] neighbors = grid.getNeighbors(index);
LatLonPointImpl refPt = new LatLonPointImpl();
LatLonPointImpl neiPt = new LatLonPointImpl();
Bearing bearing = new Bearing();
float[] hat1 = new float[2];
float[] hat2 = new float[2];
float[][] hat = new float[2][grid.getLength()];
float[][] refCoords = null;
float[][] neiCoords = null;
float[][] domainSamples = grid.getSamples(false);
refCoords = (hasCS) ? cs.toReference(Set.copyFloats(domainSamples)) : domainSamples;
// If the grid is lat/lon or has an IdentityCoordinateSystem
// don't do the rotation
// TODO: handle rotated lat/lon grids
if (!hasCS
|| (refCoords == domainSamples)
|| (Arrays.equals(refCoords[latI], domainSamples[latI])
&& Arrays.equals(refCoords[lonI], domainSamples[lonI]))) {
if (index == 0) {
Arrays.fill(hat[0], 1);
Arrays.fill(hat[1], 0);
} else {
Arrays.fill(hat[0], 0);
Arrays.fill(hat[1], 1);
}
} else {
float latBefore, lonBefore, latAfter, lonAfter;
// int backOffset = (index==0) ? -180 : 0;
// int foreOffset = (index==0) ? 0 : -180;
int backOffset = -180;
int foreOffset = 0;
for (int i = 0; i < neighbors.length; i++) {
refPt.set(refCoords[latI][i], refCoords[lonI][i]);
if ((neighbors[i][0] < 0) || (neighbors[i][0] >= neighbors.length)) {
latBefore = Float.NaN;
lonBefore = Float.NaN;
} else {
latBefore = refCoords[latI][neighbors[i][0]];
lonBefore = refCoords[lonI][neighbors[i][0]];
}
if ((neighbors[i][1] < 0) || (neighbors[i][1] >= neighbors.length)) {
latAfter = Float.NaN;
lonAfter = Float.NaN;
} else {
latAfter = refCoords[latI][neighbors[i][1]];
lonAfter = refCoords[lonI][neighbors[i][1]];
}
compute(refPt, neiPt, latBefore, lonBefore, backOffset, bearing, hat1);
float d1 = (float) bearing.getDistance();
compute(refPt, neiPt, latAfter, lonAfter, foreOffset, bearing, hat2);
float d2 = (float) bearing.getDistance();
boolean bad1 = Double.isNaN(d1);
boolean bad2 = Double.isNaN(d2);
if (bad1 && bad2) {
hat[0][i] = Float.NaN;
hat[1][i] = Float.NaN;
} else {
if (bad1) {
hat[0][i] = hat2[0];
hat[1][i] = hat2[1];
} else if (bad2) {
hat[0][i] = hat1[0];
hat[1][i] = hat1[1];
} else {
float tot = d1 + d2;
float c1 = d2 / tot;
float c2 = d1 / tot;
float xhat = c1 * hat1[0] + c2 * hat2[0];
float yhat = c1 * hat1[1] + c2 * hat2[1];
float mag = (float) Math.sqrt(xhat * xhat + yhat * yhat);
hat[0][i] = xhat / mag;
hat[1][i] = yhat / mag;
}
}
}
}
FlatField hatField =
new FlatField(
new FunctionType(
((SetType) grid.getType()).getDomain(),
new RealTupleType(
RealType.getRealType("xHat", CommonUnit.dimensionless),
RealType.getRealType("yHat", CommonUnit.dimensionless))),
grid);
hatField.setSamples(hat, false);
return hatField;
}
