/**
* Projects the arrays of longitudes and latitudes to a Cylindrical Equidistant Projection to
* bring x,y and z into a uniform coordinate system (meters).
*
* @param lons
* @param lats
* @return
*/
private Array[] prj2meters(Array lons, Array lats) {
Array[] out = new Array[2];
assert Arrays.equals(lats.getShape(), lons.getShape());
Index ltidx = Index.factory(lats.getShape());
Index lnidx = Index.factory(lons.getShape());
Array lats_prj = Array.factory(java.lang.Double.class, lats.getShape());
Array lons_prj = Array.factory(java.lang.Double.class, lons.getShape());
for (int i = 0; i < lats.getSize(); i++) {
for (int j = 0; j < lons.getSize(); j++) {
float lon_dd = lons.getFloat(lnidx.set(j));
float lat_dd = lats.getFloat(ltidx.set(i));
double[] prj = MatrixUtilities.lonlat2ceqd(new double[] {lon_dd, lat_dd});
lons_prj.setDouble(lnidx.set(j), prj[0]);
lats_prj.setDouble(ltidx.set(i), prj[1]);
}
}
out[0] = lons_prj;
out[1] = lats_prj;
return out;
}
/**
* Calculates change in the y direction
*
* @param arr - a 3x3 array of numbers
* @return
*/
private float dy(Array arr) {
Index idx = Index.factory(arr.getShape());
float e = arr.getFloat(idx.set(1, 1));
if (Float.isNaN(e)) {
return Float.NaN;
}
float a = arr.getFloat(idx.set(0, 0));
float b = arr.getFloat(idx.set(0, 1));
float c = arr.getFloat(idx.set(0, 2));
float g = arr.getFloat(idx.set(2, 0));
float h = arr.getFloat(idx.set(2, 1));
float i = arr.getFloat(idx.set(2, 2));
a = Float.isNaN(a) ? 0 : a;
b = Float.isNaN(b) ? 0 : b;
c = Float.isNaN(c) ? 0 : c;
g = Float.isNaN(g) ? 0 : g;
h = Float.isNaN(h) ? 0 : h;
i = Float.isNaN(i) ? 0 : i;
return ((g + 2 * h + i) - (a + 2 * b + c)) / 8;
}
/**
* Calculates change in the x direction
*
* @param arr - a 3x3 array of numbers
* @return
*/
private float dx(Array arr) {
Index idx = Index.factory(arr.getShape());
float e = arr.getFloat(idx.set(1, 1));
if (Float.isNaN(e)) {
return Float.NaN;
}
float a = arr.getFloat(idx.set(0, 0));
float c = arr.getFloat(idx.set(0, 2));
float d = arr.getFloat(idx.set(1, 0));
float f = arr.getFloat(idx.set(1, 2));
float g = arr.getFloat(idx.set(2, 0));
float i = arr.getFloat(idx.set(2, 2));
a = Float.isNaN(a) ? 0 : a;
c = Float.isNaN(c) ? 0 : c;
d = Float.isNaN(d) ? 0 : d;
f = Float.isNaN(f) ? 0 : f;
g = Float.isNaN(g) ? 0 : g;
i = Float.isNaN(i) ? 0 : i;
return ((c + 2 * f + i) - (a + 2 * d + g)) / 8;
}