nikos wrote: > hey list, > > Sorry that I took so much to respond, > > I'm orientating in a different direction right now, and I'd like an > opinion (on TRMM 3B43 ofc). > Another option: get binary grids from here ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/3B43_V6/ read ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/3B43_V6/3B43.ctl
import into a latlon location with r.in.bin -f -b north=50 south=-50 east=180 west=-180 rows=400 cols=1440, e.g. r.in.bin -f -b input=3B43.100101.6.precipitation.bin output=3B43.100101.6.precipitation north=50 south=-50 east=180 west=-180 rows=400 cols=1440 optionally convert mm/hr to some other time unit This can be easily scripted to automatically get and process the complete TRMM 3B43_V6 dataset. my0.2c Markus M > Here are my thoughts: > > a) the hdf that delivers the product only wraps a table 1400 long x 440 > tall. Each tile is represented by known cords. eg the upper left tile > ( [0][0] ) have the coords of -180deg, 50deg. This is a fact. And also > it is a fact the dArc from each tile to another tile (horizontally and > vertically) its 0.25arcs. > b) So we can controllably somehow "dump" the data into a csv of x,y z > where z are mm/hr (3b43 specification). x,y in a φ,λ coordinate system > (reprojections and projections are not my strong point). > > results are 1440 x 400 points with known known coords and values. > > c) interpolate for the area you're interested for. > > d) You got yourself a raster to have fun with. > > Taken into account the reprojection from φ,λ is possible and a viable > solution, the hard part seems to be getting the data. Here's my solution > on that: Giovanni Interface so kindly provided by nasa.gov . You get the > data in ascii format for the area you're researching for and free to > work with htem. > > Here's an example on data dump: > > http://disc2.nascom.nasa.gov/daac-bin/Giovanni/tovas/Giovanni_cgi.pl?west=16.0&north=43.0&east=30.0&south=31.0¶ms=1|3B43_V6&plot_type=Area+Plot&byr=2006&bmo=05&eyr=2006&emo=05&begin_date=1998/01&end_date=2010/10&cbar=cdyn&cmin=&cmax=&yaxis=ydyn&ymin=&ymax=&yint=&ascres=0.25x0.25&global_cfg=tovas.global.cfg.pl&instance_id=TRMM_V6&prod_id=3B43&action=ASCII+Output > > > My thoughts are that a python script that utilities the above method is > possible. > > Any thoughts on my comments would be really appreciated. > > > Best Regards, > Nick Ves > > > > On Mon, 2010-11-15 at 11:03 +0100, Markus Metz wrote: >> On Sun, Nov 14, 2010 at 8:41 PM, Markus Neteler <[email protected]> wrote: >> > On Sun, Nov 14, 2010 at 7:42 PM, nikos <[email protected]> wrote: >> >> On Sun, 2010-11-14 at 16:35 +0100, Markus Neteler wrote: >> >>> On Sun, Nov 14, 2010 at 4:01 PM, nikos <[email protected]> wrote: >> >>> > >> >>> > >> >>> > I'm battling to import the 43b3 Product (TRMM perspiration + other >> >>> >> >>> (http://disc.sci.gsfc.nasa.gov/precipitation/documentation/TRMM_README/TRMM_3B42_readme.shtml) >> >> You could also use the TRMM tools [1] to dump the data to a raw binary >> file. Last time I did that I noted that the binary file is rotated by >> 90°, i.e. north is right and west is up (or north is left and west is >> down, forgot the rotation direction). >> >> >> >> >> I tried >> >> >> >> ./gdal_translate -a_ullr -180 50 -50 180 >> >> HDF4_SDS:UNKNOWN:"/DIR/OF/TRMM_IMAGE/3B43.060801.6.HDF":1 test.tif >> >> >> >> which makes an interesting tif, that is not empty, but when I load it >> >> with qgis (use psedocolor) its square(?). The image should have a >> >> 1440/400 ratio. >> >> What does >> gdalinfo HDF4_SDS:UNKNOWN:"/DIR/OF/TRMM_IMAGE/3B43.060801.6.HDF":1 >> say? There should be 400 rows and 1440 columns, and not vice versa, >> 1440 rows and 400 columns (suspected 90° rotation mentioned above). >> >> > >> > Wait - AFAIK you need to use "gdalwarp" on it, not gdal_translate. >> > >> >> Hm, there is no coordinate system specified in the hdf, so gdalwarp >> would only work with -s_srs wgs84 -t_srs <something else than wgs84>. >> Or translate first, add gcps during translation, then warp? >> >> Markus M >> >> [1] >> ftp://disc2.nascom.nasa.gov/software/trmm_software/Read_HDF/READTRMM_V2.tar > > > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
