/**
* Compute DEM traversal step sizes (in degree) in latitude and longitude.
*
* @throws Exception The exceptions.
*/
private void computeDEMTraversalSampleInterval() throws Exception {
double[] latLonMinMax = new double[4];
computeImageGeoBoundary(0, sourceImageWidth - 1, 0, sourceImageHeight - 1, latLonMinMax);
final double groundRangeSpacing = SARGeocoding.getRangePixelSpacing(sourceProduct);
final double azimuthPixelSpacing = SARGeocoding.getAzimuthPixelSpacing(sourceProduct);
final double spacing = Math.min(groundRangeSpacing, azimuthPixelSpacing);
// final double spacing = (groundRangeSpacing + azimuthPixelSpacing)/2.0;
final double latMin = latLonMinMax[0];
final double latMax = latLonMinMax[1];
double minAbsLat;
if (latMin * latMax > 0) {
minAbsLat = Math.min(Math.abs(latMin), Math.abs(latMax)) * Constants.DTOR;
} else {
minAbsLat = 0.0;
}
delLat = spacing / Constants.MeanEarthRadius * Constants.RTOD;
delLon = spacing / (Constants.MeanEarthRadius * FastMath.cos(minAbsLat)) * Constants.RTOD;
delLat = Math.min(delLat, delLon); // (delLat + delLon)/2.0;
delLon = delLat;
}
/**
* Retrieve required data from Abstracted Metadata
*
* @throws Exception if metadata not found
*/
private void getMetadata() throws Exception {
srgrFlag = AbstractMetadata.getAttributeBoolean(absRoot, AbstractMetadata.srgr_flag);
wavelength = SARUtils.getRadarFrequency(absRoot);
rangeSpacing = AbstractMetadata.getAttributeDouble(absRoot, AbstractMetadata.range_spacing);
firstLineUTC = absRoot.getAttributeUTC(AbstractMetadata.first_line_time).getMJD(); // in days
lastLineUTC = absRoot.getAttributeUTC(AbstractMetadata.last_line_time).getMJD(); // in days
lineTimeInterval =
absRoot.getAttributeDouble(AbstractMetadata.line_time_interval)
/ Constants.secondsInDay; // s to day
orbitStateVectors = AbstractMetadata.getOrbitStateVectors(absRoot);
if (srgrFlag) {
srgrConvParams = AbstractMetadata.getSRGRCoefficients(absRoot);
} else {
nearEdgeSlantRange =
AbstractMetadata.getAttributeDouble(absRoot, AbstractMetadata.slant_range_to_first_pixel);
}
final TiePointGrid incidenceAngle = OperatorUtils.getIncidenceAngle(sourceProduct);
nearRangeOnLeft = SARGeocoding.isNearRangeOnLeft(incidenceAngle, sourceImageWidth);
}
private boolean getPosition(
final double lat,
final double lon,
final double alt,
final int x0,
final int y0,
final int w,
final int h,
final PositionData data) {
GeoUtils.geo2xyzWGS84(lat, lon, alt, data.earthPoint);
/*final double zeroDopplerTime = SARGeocoding.getEarthPointZeroDopplerTimeNewton(
firstLineUTC, lineTimeInterval, wavelength, data.earthPoint,
orbit.sensorPosition, orbit.sensorVelocity);*/
final double zeroDopplerTime =
SARGeocoding.getEarthPointZeroDopplerTimeNewton(
firstLineUTC, lineTimeInterval, wavelength, data.earthPoint, orbit);
if (zeroDopplerTime == SARGeocoding.NonValidZeroDopplerTime) {
return false;
}
data.slantRange =
SARGeocoding.computeSlantRange(zeroDopplerTime, orbit, data.earthPoint, data.sensorPos);
final double zeroDopplerTimeWithoutBias =
zeroDopplerTime + data.slantRange / Constants.lightSpeedInMetersPerDay;
data.azimuthIndex = (zeroDopplerTimeWithoutBias - firstLineUTC) / lineTimeInterval;
if (!(data.azimuthIndex > y0 - 1 && data.azimuthIndex <= y0 + h)) {
return false;
}
data.slantRange =
SARGeocoding.computeSlantRange(
zeroDopplerTimeWithoutBias, orbit, data.earthPoint, data.sensorPos);
if (!srgrFlag) {
data.rangeIndex = (data.slantRange - nearEdgeSlantRange) / rangeSpacing;
} else {
data.rangeIndex =
SARGeocoding.computeRangeIndex(
srgrFlag,
sourceImageWidth,
firstLineUTC,
lastLineUTC,
rangeSpacing,
zeroDopplerTimeWithoutBias,
data.slantRange,
nearEdgeSlantRange,
srgrConvParams);
}
if (data.rangeIndex <= 0.0) {
return false;
}
if (!nearRangeOnLeft) {
data.rangeIndex = sourceImageWidth - 1 - data.rangeIndex;
}
if (!(data.rangeIndex >= x0 && data.rangeIndex < x0 + w)) {
return false;
}
return true;
}
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;
}
}