[GRASS-user] Importing MODIS L2 data

[Ivan Shmakov]

>>>>> Michael Perdue <michael_perdue at yahoo.ca> writes:

 > I have a set of MODIS HDF files that I'm trying to work with.
 > Importing is fine, but the issue is the geolocation information. The
 > files store two arrays; one for latitude and one for longitude where
 > each pixel in the arrays store the latitude and longitude for the
 > corresponding Image pixel.

        I. e., it's MODIS L2 data.  (As opposed to MODIS L3 data, which
        is stored on a cartographic grid and may require you to use
        `gdalwarp' to get the geolocation in the GRASS right.)

 > Does anyone have an efficient method of using this info to re-project
 > the images from Image space into map space?

        There's a number of packages to facilitate transformation of
        MODIS swath data to cartographic grids.  Among others are the
        MODIS Swath-To-Grid Toolbox (MS2GT) [1], MODIS Reprojection Tool
        [2] and HDF-EOS to Geotiff (HEG) [3].

        Personally, I've been using MS2GT's `fornav' together with
        `proj' (from PROJ.4 [4]), `hdfdump' [5] and (unreleased, but
        available) Rawtools [6], tied into a script which makes use of
        `g.proj' and `r.in.bin' as well.  However, HEG seems to be a
        more comprehensive solution (except that the number of
        projections it currently supports is nowhere close to the vast
        set supported by PROJ.4.)

        I've never used MODIS Reprojection Tool.

        I wasn't able to find the license for either MS2GT or HEG.
        MS2GT is provided as the source code package, while HEG is
        provided, IIUC, in binary form only (for a number of platforms.)

[1] http://nsidc.org/data/modis/ms2gt/
[2] http://edcdaac.usgs.gov/landdaac/tools/modis/index.asp
[3] http://newsroom.gsfc.nasa.gov/sdptoolkit/HEG/HEGHome.html
[4] http://www.remotesensing.org/proj/
[5] http://theory.asu.ru/~ivan/devel/hdfdump/
[6] http://savannah.nongnu.org/projects/rawtools/