On Friday 24 July 2015 22:56:42 Michael Sumner wrote: > Hello, I've put together an example of using NSDIC sea ice concentration > data with GDAL VRT. > > In this Github readme I list two example data sets, one for the Northern > and one for the Southern hemisphere where the raw > binary NSDIC .bin files have accompanying VRT files: > > https://github.com/mdsumner/NSIDC-seaice > > I'd really like to see this format as a GDAL driver, but I don't have the > C++ expertise to make it happen. I can offer help and testing if anyone was > interested in writing the driver, but I would also appreciate any guidance > and kick start for me to learn to do it myself. > > The format itself is detailed here, and everything required can be gleaned > from the header - though in the VRT pathway I simply skip the header and > apply the right CRS, orientation, grid size and geotransform: > > http://nsidc.org/data/docs/daac/nsidc0051_gsfc_seaice.gd.html#format > > The repo includes the minimal .vrt required to read this as a valid GDAL > data set and uses plotting in R with standard R > mapping tools to show that the interpretation is right, at least visibly. > > I have these questions: > > * what is the best template driver for these data, should it derive from > GDALPamDataset like JDEM or from RawDataset as ERS does? (I'm way out of > my depth here)
Mike, Deriving from RawDataset is certainly the best option here. You can take exemple on drivers in frmts/raw/ > * is it appropriate to use this SRS when the datum is unspecified? I'm not > clear on the pitfalls here and how to advise downstream use Do you mean EPSG 3411 and 3412 ? Well, why not... ? > > I am competent with building GDAL but I get lost in the steps required to > add a new driver. A dummy example, or some more detailed guidance for how I > would apply the "GDAL Driver Implementation Tutorial" to these data would > be enough for me to flesh out the details. You'll basically have to use a new file and reference it in frmts/raw/GNUmakefile and makefile.vc, as well as declaring the driver register function in gcore/gdal_frmts.h and calling it in frmts/gdalallregister.cpp Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
