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

[Markus Müller]

I submitted a ticket regarding this issue:https://trac.osgeo.org/gdal/ticket/6051


Thanks Andre for your help on gis.stackexchange and here.




Cheers,


Markus Mueller




---- On Sun, 26 Jul 2015 09:34:58 -0700 Andre Joost <andre+joost at nurfuerspam.de> wrote ---- 

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. 
> 
> 
> 
> _______________________________________________ 
> gdal-dev mailing list 
> gdal-dev at lists.osgeo.org 
> http://lists.osgeo.org/mailman/listinfo/gdal-dev 
> 
 
 
_______________________________________________ 
gdal-dev mailing list 
gdal-dev at lists.osgeo.org 
http://lists.osgeo.org/mailman/listinfo/gdal-dev 





-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20150726/c06b2ffd/attachment.html>