private void computeTileOverlapPercentage(
final int x0, final int y0, final int w, final int h, double[] overlapPercentages)
throws Exception {
final PixelPos pixPos = new PixelPos();
final GeoPos geoPos = new GeoPos();
final PosVector earthPoint = new PosVector();
final PosVector sensorPos = new PosVector();
double tileOverlapPercentageMax = -Double.MAX_VALUE;
double tileOverlapPercentageMin = Double.MAX_VALUE;
for (int y = y0; y < y0 + h; y += 20) {
for (int x = x0; x < x0 + w; x += 20) {
pixPos.setLocation(x, y);
sourceGeoCoding.getGeoPos(pixPos, geoPos);
final double alt = dem.getElevation(geoPos);
GeoUtils.geo2xyzWGS84(geoPos.getLat(), geoPos.getLon(), alt, earthPoint);
final double zeroDopplerTime =
SARGeocoding.getEarthPointZeroDopplerTime(
firstLineUTC,
lineTimeInterval,
wavelength,
earthPoint,
orbit.sensorPosition,
orbit.sensorVelocity);
if (zeroDopplerTime == SARGeocoding.NonValidZeroDopplerTime) {
continue;
}
final double slantRange =
SARGeocoding.computeSlantRange(zeroDopplerTime, orbit, earthPoint, sensorPos);
final double zeroDopplerTimeWithoutBias =
zeroDopplerTime + slantRange / Constants.lightSpeedInMetersPerDay;
final int azimuthIndex =
(int) ((zeroDopplerTimeWithoutBias - firstLineUTC) / lineTimeInterval + 0.5);
double tileOverlapPercentage = (double) (azimuthIndex - y) / (double) tileSize;
if (tileOverlapPercentage > tileOverlapPercentageMax) {
tileOverlapPercentageMax = tileOverlapPercentage;
}
if (tileOverlapPercentage < tileOverlapPercentageMin) {
tileOverlapPercentageMin = tileOverlapPercentage;
}
}
}
if (tileOverlapPercentageMin != Double.MAX_VALUE && tileOverlapPercentageMin < 0.0) {
overlapPercentages[0] = tileOverlapPercentageMin - 0.5;
} else {
overlapPercentages[0] = 0.0;
}
if (tileOverlapPercentageMax != -Double.MAX_VALUE && tileOverlapPercentageMax > 0.0) {
overlapPercentages[1] = tileOverlapPercentageMax + 0.5;
} else {
overlapPercentages[1] = 0.0;
}
}
