Re: MODIS HDF

Thanks Dennis and David.

I am still unfortunately getting a segmentation fault with
the edited code below.
(I believe I correctly implemented your suggestions, but
let me know if I messed up anywhere)

By the way, how do I verify the projection type? I suspect
it is sinusoidal but am not sure.

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
begin

; 1km annual npp modis on 1200x1200 tiles

a=addfile("/Users/notaro/downloads/Y2000/MOD17A3.A2000366.h11v11.305.2009342143541.hdf.hdfeos","r")

lat2d=a->GridLat_MOD_Grid_MOD17A3
lon2d=a->GridLon_MOD_Grid_MOD17A3

npp=short2flt(a->Npp_1km_MOD_Grid_MOD17A3)

npp!0="nlat"
npp!1="nlon"
npp@coordinates="lat2d lon2d"
npp@projection="sinusoidal"

lat2d!0="nlat"
lat2d!1="nlon"
lon2d!0="nlat"
lon2d!1="nlon"

printVarSummary(npp)

system("rm test.nc")
out=addfile("test.nc","c")
out->npp=npp
out->lat2d=lat2d
out->lon2d=lon2d

end

Variable: npp
Type: float
Total Size: 5760000 bytes
            1440000 values
Number of Dimensions: 2
Dimensions and sizes: [nlat | 1200] x [nlon | 1200]
Coordinates:
Number Of Attributes: 5
  _FillValue : 1e+20
  coordinates : lat2d lon2d
  hdfeos_name : Npp_1km
  projection : sinusoidal
  unsigned : True

On Aug 30, 2011, at 1:16 PM, Dennis Shea wrote:

>
>
> On 8/30/11 12:14 PM, Dennis Shea wrote:
>>
>>
>> npp!0="nlat"
>> npp!1="nlon"
>> ;;npp@lat2d=lat2d ; no ... only for graphics
>> ;;npp@lon2d=lon2d ; no
>> npp@coordinates="lat2d lon2d"
>> npp@projection="sinusoidal"
>
> lat2d!0 = "nlat"
> lat2d!1 = "nlon"
> lon2d!0 = "nlat"
> lon2d!1 = "nlon"
>
>>
>> printVarSummary(npp)
>>
>> system("/bin/rm -f test.nc")
>> out=addfile("test.nc","c")
>> out->npp=npp
>> out->lat2d=lat2d
>> out->lon2d=lon2d
>>
>>
>> On 8/30/11 12:05 PM, Michael Notaro wrote:
>>> Thanks Dennis. Using hdfeof helps a lot and gives me the lats/lons now.
>>>
>>> Seems I am having another problem. After I read the hdfeos and retrieve
>>> the lats/lons and data, I tried writing it to a file and always get segmentation fault.
>>> What am I doing wrong?
>>>
>>>
>>>
>>>
>>>
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
>>> begin
>>>
>>> ; 1km annual npp modis on 1200x1200 tiles
>>>
>>> a=addfile("/Users/notaro/downloads/Y2000/MOD17A3.A2000366.h11v11.305.2009342143541.hdf.hdfeos","r")
>>>
>>> lat2d=a->GridLat_MOD_Grid_MOD17A3
>>> lon2d=a->GridLon_MOD_Grid_MOD17A3
>>>
>>> npp=short2flt(a->Npp_1km_MOD_Grid_MOD17A3)
>>>
>>> npp!0="lat2d"
>>> npp!1="lon2d"
>>> npp@lat2d=lat2d
>>> npp@lon2d=lon2d
>>> npp@coordinates="lat2d lon2d"
>>> npp@projection="sinusoidal"
>>>
>>> printVarSummary(npp)
>>>
>>> out=addfile("test.nc","c")
>>> out->npp=npp
>>> out->lat2d=lat2d
>>> out->lon2d=lon2d
>>>
>>> end
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Variable: npp
>>> Type: float
>>> Total Size: 5760000 bytes
>>> 1440000 values
>>> Number of Dimensions: 2
>>> Dimensions and sizes: [lat2d | 1200] x [lon2d | 1200]
>>> Coordinates:
>>> Number Of Attributes: 7
>>> lon2d : <ARRAY of 1440000 elements>
>>> lat2d : <ARRAY of 1440000 elements>
>>> _FillValue : 1e+20
>>> coordinates : lat2d lon2d
>>> hdfeos_name : Npp_1km
>>> projection : sinusoidal
>>> unsigned : True
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Aug 30, 2011, at 12:44 PM, Dennis Shea wrote:
>>>
>>>> Mike
>>>>
>>>> [1]
>>>> %> ncl_filedump MOD17A3.A2010365.h00v08.305.2011029145245.hdf
>>>>
>>>> yields
>>>>
>>>> Variable: f
>>>> Type: file
>>>> filename: MOD17A3.A2010365.h00v08.305.2011029145245
>>>> path: MOD17A3.A2010365.h00v08.305.2011029145245.hdf
>>>> file global attributes:
>>>> HDFEOSVersion : HDFEOS_V2.16
>>>> StructMetadata_0 : GROUP=SwathStructure
>>>> END_GROUP=SwathStructure
>>>> GROUP=GridStructure
>>>> GROUP=GRID_1
>>>> GridName="MOD_Grid_MOD17A3"
>>>> XDim=1200
>>>> YDim=1200
>>>> UpperLeftPointMtrs=(-20015109.354000,1111950.519667)
>>>> LowerRightMtrs=(-18903158.834333,0.000000)
>>>> Projection=GCTP_SNSOID
>>>> [SNIP]
>>>>
>>>> [2]
>>>> If you append the '.hdfeos' suffix, you will get that lat/lon values.
>>>>
>>>> %> ncl_filedump MOD17A3.A2010365.h00v08.305.2011029145245.hdf.hdfeos
>>>>
>>>> Variable: f
>>>> Type: file
>>>> filename: MOD17A3.A2010365.h00v08.305.2011029145245.hdf
>>>> path: MOD17A3.A2010365.h00v08.305.2011029145245.hdf
>>>> file global attributes:
>>>> dimensions:
>>>> YDim_MOD_Grid_MOD17A3 = 1200
>>>> XDim_MOD_Grid_MOD17A3 = 1200
>>>> variables:
>>>> double GridLat_MOD_Grid_MOD17A3 ( YDim_MOD_Grid_MOD17A3,
>>>> XDim_MOD_Grid_MOD17A3 )
>>>> projection : (null)
>>>> corners : ( 9.995833332438675, 9.995833332438675,
>>>> 0.004166666666293064, 0.004166666666293064 )
>>>> long_name : latitude
>>>> units : degrees_north
>>>>
>>>> double GridLon_MOD_Grid_MOD17A3 ( YDim_MOD_Grid_MOD17A3,
>>>> XDim_MOD_Grid_MOD17A3 )
>>>> projection : (null)
>>>> corners : ( 177.2297839752788, -172.6245418649626,
>>>> -170.00416710093, -179.9958337931229 )
>>>> long_name : longitude
>>>> units : degrees_east
>>>> [snip]
>>>>
>>>> [3] Use the hdfeos suffix. The names are different than using 'just' hdf
>>>> however NCL does provide the georeferenced data coordinates.
>>>>
>>>>
>>>> [4] You might look at:
>>>>
>>>> http://www.ncl.ucar.edu/Applications/binning.shtml
>>>>
>>>> Good luck
>>>> D
>>>>
>>>>
>>>>
>>>>
>>>> On 8/30/11 11:23 AM, Michael Notaro wrote:
>>>>> 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 12:25:25 2011