<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta content="text/html;charset=UTF-8" http-equiv="Content-Type"></head><body ><div style='font-size:10pt;font-family:Verdana,Arial,Helvetica,sans-serif;'>I submitted a ticket regarding this issue:<div>https://trac.osgeo.org/gdal/ticket/6051</div><div><br></div><div>Thanks Andre for your help on gis.stackexchange and here.</div><div><br></div><div><br></div><div>Cheers,</div><div><br></div><div>Markus Mueller</div><div><br></div><div><br><div class="zmail_extra"><div id="1"><br>---- On Sun, 26 Jul 2015 09:34:58 -0700 <b>Andre Joost <andre+joost@nurfuerspam.de></b> wrote ---- <br></div><blockquote style="border-left: 1px solid #0000FF;padding-left: 6px; margin: 0 0 0 5px">Can this VRT approach be used for MODIS sea ice data too? <br> <br><a href="http://gis.stackexchange.com/questions/112547/reprojecting-modis-ice-sea-temperature-products-with-gdalwarp" target="_blank">http://gis.stackexchange.com/questions/112547/reprojecting-modis-ice-sea-temperature-products-with-gdalwarp</a> <br> <br><a href="http://gis.stackexchange.com/questions/155326/reprojecting-modis-sea-ice-extent-and-ist-data-using-gdal" target="_blank">http://gis.stackexchange.com/questions/155326/reprojecting-modis-sea-ice-extent-and-ist-data-using-gdal</a> <br> <br>note that especially older versions (before 2011) only produce garbage <br>images with GDAL. <br> <br>Greetings, <br>André Joost <br> <br>Am 25.07.2015 um 00:56 schrieb Michael Sumner: <br>> Hello, I've put together an example of using NSDIC sea ice concentration <br>> data with GDAL VRT. <br>> <br>> In this Github readme I list two example data sets, one for the Northern <br>> and one for the Southern hemisphere where the raw <br>> binary NSDIC .bin files have accompanying VRT files: <br>> <br>> <a href="https://github.com/mdsumner/NSIDC-seaice" target="_blank">https://github.com/mdsumner/NSIDC-seaice</a> <br>> <br>> I'd really like to see this format as a GDAL driver, but I don't have the <br>> C++ expertise to make it happen. I can offer help and testing if anyone was <br>> interested in writing the driver, but I would also appreciate any guidance <br>> and kick start for me to learn to do it myself. <br>> <br>> The format itself is detailed here, and everything required can be gleaned <br>> from the header - though in the VRT pathway I simply skip the header and <br>> apply the right CRS, orientation, grid size and geotransform: <br>> <br>> <a href="http://nsidc.org/data/docs/daac/nsidc0051_gsfc_seaice.gd.html#format" target="_blank">http://nsidc.org/data/docs/daac/nsidc0051_gsfc_seaice.gd.html#format</a> <br>> <br>> The repo includes the minimal .vrt required to read this as a valid GDAL <br>> data set and uses plotting in R with standard R <br>> mapping tools to show that the interpretation is right, at least visibly. <br>> <br>> I have these questions: <br>> <br>> * what is the best template driver for these data, should it derive from <br>> GDALPamDataset like JDEM or from RawDataset as ERS does? (I'm way out of <br>> my depth here) <br>> * is it appropriate to use this SRS when the datum is unspecified? I'm not <br>> clear on the pitfalls here and how to advise downstream use <br>> <br>> I am competent with building GDAL but I get lost in the steps required to <br>> add a new driver. A dummy example, or some more detailed guidance for how I <br>> would apply the "GDAL Driver Implementation Tutorial" to these data would <br>> be enough for me to flesh out the details. <br>> <br>> The projection SRS used are EPSG 3411 (north) and 3412 (south) as listed <br>> here: <br>> <a href="http://spatialreference.org/ref/epsg/3411/" target="_blank">http://spatialreference.org/ref/epsg/3411/</a> <br>> <a href="http://spatialreference.org/ref/epsg/3412/" target="_blank">http://spatialreference.org/ref/epsg/3412/</a> <br>> <br>> I have otherwise written this support directly into the R package raster, <br>> the R source for these files is here in this read-only mirror (raster is on <br>> r-forge): <br>> <br>> <a href="https://github.com/cran/raster/blob/master/R/nsidcICE.R" target="_blank">https://github.com/cran/raster/blob/master/R/nsidcICE.R</a> <br>> <br>> This works very well for R, but I'd prefer to see this format in GDAL so <br>> that other languages have the same facility. There are other sea ice <br>> concentration data sources, usually in HDF4 format - and they only need the <br>> geotransform and SRS assigned for use in GDAL - so they need work as well <br>> but not as fundamental as this raw binary format. This data source is very <br>> extensive, with daily data at 25km resolution every day since 1979 with <br>> only ~30 days total missing, and only a handful with problems in the map <br>> coverage. <br>> <br>> Thank you. <br>> <br>> Cheers, Mike. <br>> <br>> <br>> <br>> _______________________________________________ <br>> gdal-dev mailing list <br>> <a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a> <br>> <a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a> <br>> <br> <br> <br>_______________________________________________ <br>gdal-dev mailing list <br><a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a> <br><a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a> <br></blockquote><br></div><br></div></div></body></html>