I’ve a hard time understanding which one should be the correct result by gdal_translate or GeoServer.
My system (Ubuntu 22.04) has:
GDAL 3.4.1
Geoserver 2.22 running on Tomcat on port 9090
I have a small tiff file (link to download at the bottom of this thread) in EPSG:4326, then I wanted to have a small subset on Lat and Long axes from it by running:
Also the geo bbox of gdal.tif and geoserver.tif are different.
First file gives:
Upper Left ( 136.9750000, -35.9750000)
Second file gives:
Upper Left ( 137.9750000, -36.9750000)
More importantly, the pixels are shifted from gdal.tif at the top to geoserver.tif at the bottom which you can see from this image: https://imgur.com/a/L0vKvYk
I find WCS tricky to use, did you use the WCS Request Builder to produce your curl command?
One thing I could not determine from your curl example is what what target coverage layout is being used (which is probably what your question is about). I am not sure if WCS 2 allows you to specify that manually or not.
Given your raster contains both shifted pixels and one additional row than anticipated by gdal. This may be a difference between sampling at the grid locations defined (WCS), rather that defining a grid of pixels and sampling in the middle of each pixel defined (gdal)?
I find WCS tricky to use, did you use the WCS Request Builder to produce your curl command?
No, I didn’t use any tool for that. The parameters in curl command are standard WCS 2.0.1 GetCoverage request.
One thing I could not determine from your curl example is what what target coverage layout is being used (which is probably what your question is about). I am not sure if WCS 2 allows you to specify that manually or not.
I’m not sure about this either. I used only standard parameters request for WCS GetCoverage.
Given your raster contains both shifted pixels and one additional row than anticipated by gdal. This may be a difference between sampling at the grid locations defined (WCS), rather that defining a grid of pixels and sampling in the middle of each pixel defined (gdal)?
I’m not sure about this either. I used GeoServer normally to create a data source as one TIFF file, then published it as a Layer and I didn’t define any grid locations.
I find WCS tricky to use, did you use the WCS Request Builder to produce your curl command?
One thing I could not determine from your curl example is what what target coverage layout is being used (which is probably what your question is about). I am not sure if WCS 2 allows you to specify that manually or not.
Given your raster contains both shifted pixels and one additional row than anticipated by gdal. This may be a difference between sampling at the grid locations defined (WCS), rather that defining a grid of pixels and sampling in the middle of each pixel defined (gdal)?
I’ve a hard time understanding which one should be the correct result by gdal_translate or GeoServer.
My system (Ubuntu 22.04) has:
GDAL 3.4.1
Geoserver 2.22 running on Tomcat on port 9090
I have a small tiff file (link to download at the bottom of this thread) in EPSG:4326, then I wanted to have a small subset on Lat and Long axes from it by running:
Also the geo bbox of gdal.tif and geoserver.tif are different.
First file gives:
Upper Left ( 136.9750000, -35.9750000)
Second file gives:
Upper Left ( 137.9750000, -36.9750000)
More importantly, the pixels are shifted from gdal.tif at the top to geoserver.tif at the bottom which you can see from this image: https://imgur.com/a/L0vKvYk
To our request defines the grid locations, you may have to read the standard to determine exactly how the grid is defined for your request. The standard is available on the OGC website.
I even tested with GeoTools v29-snapshot with this code below and it returned size 18 x 5 instead of 17 x 3 for gdal_translate or 17 x 4 for geoserver WCS GetCoverage.
I thought using geotools should yield the same result as geoserver WCS GetCoverage, but it is not.
Do you have any suggestions for the code before?
File file = new File("/home/aaa/Downloads/temp/test.tif");
Hints hint = new Hints();
hint.put(Hints.DEFAULT_COORDINATE_REFERENCE_SYSTEM, WGS84);
hint.put(Hints.FORCE_LONGITUDE_FIRST_AXIS_ORDER, Boolean.TRUE);
GeoTiffReader reader = new GeoTiffReader(file, hint);
GridCoverage2D coverage = reader.read(null);
CoverageProcessor processor = CoverageProcessor.getInstance();
final ParameterValueGroup param = processor.getOperation("CoverageCrop").getParameters();
// 137.915315044103 -36.51629558851893 154.64770004642423 -40.081875882617666
double minLong = 137.915315044103;
double maxLong = 154.64770004642423;
double minLat = -40.081875882617666;
double maxLat = -36.51629558851893;
final GeneralEnvelope crop = new GeneralEnvelope(new GeographicBoundingBoxImpl(minLong, maxLong,
minLat, maxLat));
ReferencedEnvelope envelope = new ReferencedEnvelope(new Envelope(minLong, maxLong,
minLat, maxLat), WGS84);
param.parameter("Source").setValue(coverage);
param.parameter("Envelope").setValue(envelope);
GridCoverage2D cropped = (GridCoverage2D) processor.doOperation(param);
GridCoverageFactory gcf = new GridCoverageFactory();
GridCoverage2D gc = gcf.create("name", cropped.getRenderedImage(), cropped.getEnvelope());
String url = "/tmp/geotools.tif";
File outputFile = new File(url);
GeoTiffWriter writer = new GeoTiffWriter(outputFile);
writer.write(gc, null);
writer.dispose();
To our request defines the grid locations, you may have to read the standard to determine exactly how the grid is defined for your request. The standard is available on the OGC website.
I find WCS tricky to use, did you use the WCS Request Builder to produce your curl command?
No, I didn’t use any tool for that. The parameters in curl command are standard WCS 2.0.1 GetCoverage request.
One thing I could not determine from your curl example is what what target coverage layout is being used (which is probably what your question is about). I am not sure if WCS 2 allows you to specify that manually or not.
I’m not sure about this either. I used only standard parameters request for WCS GetCoverage.
Given your raster contains both shifted pixels and one additional row than anticipated by gdal. This may be a difference between sampling at the grid locations defined (WCS), rather that defining a grid of pixels and sampling in the middle of each pixel defined (gdal)?
I’m not sure about this either. I used GeoServer normally to create a data source as one TIFF file, then published it as a Layer and I didn’t define any grid locations.
I find WCS tricky to use, did you use the WCS Request Builder to produce your curl command?
One thing I could not determine from your curl example is what what target coverage layout is being used (which is probably what your question is about). I am not sure if WCS 2 allows you to specify that manually or not.
Given your raster contains both shifted pixels and one additional row than anticipated by gdal. This may be a difference between sampling at the grid locations defined (WCS), rather that defining a grid of pixels and sampling in the middle of each pixel defined (gdal)?
I’ve a hard time understanding which one should be the correct result by gdal_translate or GeoServer.
My system (Ubuntu 22.04) has:
GDAL 3.4.1
Geoserver 2.22 running on Tomcat on port 9090
I have a small tiff file (link to download at the bottom of this thread) in EPSG:4326, then I wanted to have a small subset on Lat and Long axes from it by running:
Also the geo bbox of gdal.tif and geoserver.tif are different.
First file gives:
Upper Left ( 136.9750000, -35.9750000)
Second file gives:
Upper Left ( 137.9750000, -36.9750000)
More importantly, the pixels are shifted from gdal.tif at the top to geoserver.tif at the bottom which you can see from this image: https://imgur.com/a/L0vKvYk
Good idea checking with GeoTools, sadly I should step asside and someone more experienced then me answer your questions about WCS.
Still if you are comfortable with GeoTools you may wish to step through the GetCoverage operation in a debugger to see how it is coming up with the final grid.
The whole thing really seems like off by one assumptions. Between different grid coverage models. Does the actual WCS standard provide anything that can help?