For quite some time now I've been wresteling with a problem concerning projections. I was wondering if the experts on this forum/mailinglist could be of any help, since (let's face it) the material is quite frankly over my head.
The short story is that I have got an hdf5 radar image, which contains an x-y grid of pixelvalues and I have to place it on a google map. Already there's a problem because the data is purely an x-y grid and google maps uses the EPSG 3857projection. The proj4 string provided in the hdf5 file is one of the RD-coordinate system, a system used in the Netherlands.
The rest of the information I can find is listed here
cal_data_count = 0
map_projection (6024, 2)
geographic (5200, 2)
Right now I am using a complex code to rewrite each of the pixels to lat/lon & I plot them with matplotlib (python) on a mpl basemap without landcontours, coast-contours so I have an image on an mpl-basemap, but as said, without the countrycontours & such. The projecction used for the Basemap is "mercator". The result gives the desired radarimage & seems to match the locations... so far so good but with the python mapping of pixels to lat/lons...
I then run the output (a png file) through gdal to tile it, & warp it to the EPSG 3857 projection (Gmaps). When turning on the country-contours to check the result, the result is not correct, although it comes close to what it should be.
I am starting to wonder if there's another way I can make this work, perhaps without the use of matplotlib python? Eg, going from the standard x-y grid Hdf5 data straight to a warp using gdal or whichever way possible. I have run out of ideas & the information I can find to help me get passed this is really confusing.
I am looking forward to the reply of the masters in this forum.
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If you are on Windows and you are lucky that the file internals are recognized the easiest way is to use Mirone (w3.ualg.pt/~jluis/mirone). A simple drag-n-drop plus a click on the GE icon should do the job. (but you'll need to update with "Help -> check for updates).
Another option is to reproject with gdalwarp and use GMT to produce a nice image and a kml (the ps2raster (now called psconvert) module)
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