[gdal-dev] guidance on NSIDC Sea Ice concentration data

[Andre Joost]

Can this VRT approach be used for MODIS sea ice data too?

http://gis.stackexchange.com/questions/112547/reprojecting-modis-ice-sea-temperature-products-with-gdalwarp

http://gis.stackexchange.com/questions/155326/reprojecting-modis-sea-ice-extent-and-ist-data-using-gdal

note that especially older versions (before 2011) only produce garbage 
images with GDAL.

Greetings,
André Joost

Am 25.07.2015 um 00:56 schrieb Michael Sumner:
> 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)
> * 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
>
> 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.
>
> The projection SRS used are EPSG 3411 (north) and 3412 (south) as listed
> here:
> http://spatialreference.org/ref/epsg/3411/
> http://spatialreference.org/ref/epsg/3412/
>
> I have otherwise written this support directly into the R package raster,
> the R source for these files is here in this read-only mirror (raster is on
> r-forge):
>
> https://github.com/cran/raster/blob/master/R/nsidcICE.R
>
> This works very well for R, but I'd prefer to see this format in GDAL so
> that other languages have the same facility. There are other sea ice
> concentration data sources, usually in HDF4 format - and they only need the
> geotransform and SRS assigned for use in GDAL - so they need work as well
> but not as fundamental as this raw binary format.  This data source is very
> extensive, with daily data at 25km resolution every day since 1979 with
> only ~30 days total missing, and only a handful with problems in the map
> coverage.
>
> Thank you.
>
> Cheers, Mike.
>
>
>
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