Hi!
Since I'm new here, I would first like to thank all GeoTools developers for
their hard work and an excellent product! I already successfully use it to
import and export vector spatial data into my application.
Now, I want to implement a functionality to georeference drone imagery (with no
location or orientation data). I haven't found a tutorial on how to do this, so
I essentially copied the process as coded for the uDig application:
http://www.programcreek.com/java-api-examples/index.php?source_dir=udig-community-master/axios/udig-image-georeferencing/plugins/es.axios.udig.georeferencing/src/es/axios/udig/georeferencing/internal/process/GeoReferencingProcess.java
Here is my code:
public void startGeoreferencing(HashMap<Point, Placemark>
georeferencingMap, RenderedImage image)
{
// georeferencingMap is a map of user collected anchor points on the
image
// (hashmap keys) and on the map (hashmap values)
if (georeferencingMap == null || georeferencingMap.size() < 3) {
return;
}
Point2D[] srcCoords = new Point2D[georeferencingMap.size()];
Point2D[] dstCoords = new Point2D[georeferencingMap.size()];
Iterator<Point> iterator = georeferencingMap.keySet().iterator();
for (int i = 0; i < georeferencingMap.size(); i++) {
if (!iterator.hasNext()) {
break;
}
Point p = iterator.next();
Placemark pl = georeferencingMap.get(p);
List<Coordinate> c = ((KmlPoint)pl.getGeometry()).getCoordinates();
srcCoords[i] = p;
dstCoords[i] = new Point2D.Double(c.get(0).getLatitude(),
c.get(0).getLongitude());
}
WarpTransform2D warpTransform = new WarpTransform2D(srcCoords,
dstCoords, 1);
CoordinateReferenceSystem baseCrs = null;
try {
baseCrs = CRS.decode("EPSG:4326");
} catch (FactoryException ex) {
Exceptions.printStackTrace(ex);
}
DefaultDerivedCRS derivedCRS = new DefaultDerivedCRS("imageCRS",
baseCrs, warpTransform, DefaultCartesianCS.GENERIC_2D);
GridCoverageFactory factory = new GridCoverageFactory();
ReferencedEnvelope envelope = new ReferencedEnvelope(0,
image.getWidth(), 0, image.getHeight(), derivedCRS);
GridCoverage2D coverage = factory.create("GridCoverage", image,
envelope);
// Resample the image with the world CRS
GridCoverage2D warpedCoverage = null;
try {
System.setProperty("com.sun.media.jai.disableMediaLib", "true");
Operations ops = new Operations(null);
Coverage resample = ops.resample(coverage, baseCrs);
warpedCoverage = (GridCoverage2D) resample;
} catch (Exception e) {
return;
}
saveImage(warpedCoverage);
}
I get no errors, but the resulting geoTiff is always highly skewed and waaaay
too large (download example tiff: http://x.k00.fr/6eb39). I'm not sure what I'm
doing wrong and I'm kindly asking you to help me out.
Best regards,
Marko
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