catalog-editor generates invalid WGS84 bbox
Opened this issue · 3 comments
(original discussion here)
Original bbox:
"x": {
"axis": "x",
"extent": [
900000,
7400000
],
"reference_system": "3035",
"type": "spatial",
"unit": "metre",
"step": 10
},
"y": {
"axis": "y",
"extent": [
900000,
5500000
],
"reference_system": "3035",
"type": "spatial",
"unit": "metre",
"step": -10
},
The catalog editor generates a max lat coordinate 58.95275, but the correct one is 72.66. This is likely because it transforms individual coordinates which is incorrect. This can be verified with gdaltransform:
$ gdaltransform -s_srs EPSG:3035 -t_srs EPSG:4326
Enter X Y [Z [T]] values separated by space, and press Return.
7400000 5500000
72.906136759009 58.9527510923263 0
It gives 58.952 like the catalog-editor and not 72.66.
The correct way is to transform the whole bbox, e.g. with gdalwarp:
- Create a bbox_epsg3035.vrt file with content
<VRTDataset rasterXSize="650000" rasterYSize="460000">
<SRS>EPSG:3035</SRS>
<GeoTransform>900000, 10, 0, 5500000, 0, -10</GeoTransform>
<VRTRasterBand dataType="Byte" band="1">
<NoDataValue>0</NoDataValue>
<SimpleSource>
<SourceFilename relativeToVRT="1">dummy.tif</SourceFilename>
<SourceBand>1</SourceBand>
<SourceProperties RasterXSize="1" RasterYSize="1" DataType="Byte" BlockXSize="1" BlockYSize="1"/>
<SrcRect xOff="0" yOff="0" xSize="1" ySize="1"/>
<DstRect xOff="0" yOff="0" xSize="1" ySize="1"/>
</SimpleSource>
</VRTRasterBand>
</VRTDataset>- put whatever dummy.tif file in the same directory, it's irrelevant because all information is in the VRT file, but it's required.
- check the bbox with gdalinfo:
Origin = (900000.000000000000000,5500000.000000000000000)
Pixel Size = (10.000000000000000,-10.000000000000000)
Corner Coordinates:
Upper Left ( 900000.000, 5500000.000) ( 56d30'18.51"W, 56d29' 4.75"N)
Lower Left ( 900000.000, 900000.000) ( 23d49'33.58"W, 24d17' 3.04"N)
Upper Right ( 7400000.000, 5500000.000) ( 72d54'22.09"E, 58d57' 9.90"N)
Lower Right ( 7400000.000, 900000.000) ( 40d39'45.75"E, 25d32'40.96"N)
- reproject the file:
gdalwarp -t_srs EPSG:4326 -of VRT bbox_epsg3035.vrt bbox_epsg4326.vrt
- check the result bbox with
gdalinfo bbox_epsg4326.vrt:
Origin = (-56.505141901704370,72.663269668344356)
Pixel Size = (0.000128060211603,-0.000128060211603)
Corner Coordinates:
Upper Left ( -56.5051419, 72.6632697) ( 56d30'18.51"W, 72d39'47.77"N)
Lower Left ( -56.5051419, 24.2841707) ( 56d30'18.51"W, 24d17' 3.01"N)
Upper Right ( 72.9061049, 72.6632697) ( 72d54'21.98"E, 72d39'47.77"N)
Lower Right ( 72.9061049, 24.2841707) ( 72d54'21.98"E, 24d17' 3.01"N)
The reprojection is done on the client side, using a library reproject-bbox which is using proj4 as it's dependecy.
I'm aware with the distortion related shift in coordinates near (lat 60, -60) from/to WGS84, I tested some wms samples ( in our backend case, and it was fine).
I'll do more invistigation and see what it is can be done in this case.
Any updates?
