MODIS HDF

I am trying to work with MODIS HDF data of the land variable 1-km annual NPP (net primary productivity).

ftp://ftp.ntsg.umt.edu/pub/MODIS/Mirror/MOD17_Science_2010/MOD17A3/

Each file is on a separate tile. I put the info below on a sample file's
info on the variable Npp_1km and the 1200x1200 grid and bounding rectangle.

It is my understanding that I should grab the rectangles that overlap my study region,
which is Wisconsin. I think 4 of them overlap it.

I can read in the data with addfile (or use ncl_convert2nc). But I am not sure
how to retrieve the proper lats/lons to plot the data correctly. I used short2flt also
when reading it. I am guessing that the data grid must not be a normal rectangle but
stretched as the satellite moves, since the range of the lats is 10 degrees but the
range of the lons is 60 degrees.

Any suggestions on how to plot this in NCL is appreciated.

Michael

        YDim_MOD_Grid_MOD17A3 = 1200 ;
        XDim_MOD_Grid_MOD17A3 = 1200 ;

        short Npp_1km(YDim_MOD_Grid_MOD17A3, XDim_MOD_Grid_MOD17A3) ;
                Npp_1km:hdf_name = "Npp_1km" ;
                Npp_1km:units = "kg_C/m^2" ;
                Npp_1km:long_name = "MOD17A3 NPP--MODIS Gridded 1KM Annual Net Primary Productivity (NPP)" ;
                Npp_1km:_FillValue = -1s ;
                Npp_1km:valid_range = 0s, -36s ;
                Npp_1km:calibrated_nt = 23 ;
                Npp_1km:add_offset_err = 0. ;
                Npp_1km:add_offset = 0. ;
                Npp_1km:scale_factor_err = 0. ;
                Npp_1km:scale_factor = 0.0001 ;

                        " OBJECT = NORTHBOUNDINGCOORDINATE\n",
                        " NUM_VAL = 1\n",
                        " VALUE = 69.9999999937138\n",
                        " END_OBJECT = NORTHBOUNDINGCOORDINATE\n",
                        "\n",
                        " OBJECT = SOUTHBOUNDINGCOORDINATE\n",
                        " NUM_VAL = 1\n",
                        " VALUE = 59.9999999946118\n",
                        " END_OBJECT = SOUTHBOUNDINGCOORDINATE\n",
                        "\n",
                        " OBJECT = EASTBOUNDINGCOORDINATE\n",
                        " NUM_VAL = 1\n",
                        " VALUE = -119.983333303015\n",
                        " END_OBJECT = EASTBOUNDINGCOORDINATE\n",
                        "\n",
                        " OBJECT = WESTBOUNDINGCOORDINATE\n",
                        " NUM_VAL = 1\n",
                        " VALUE = -179.999999938971\n",
                        " END_OBJECT = WESTBOUNDINGCOORDINATE\n",
                        "\n",

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Received on Tue Aug 30 11:23:20 2011