Open MYD09GQ.A2006060.h25v06.005.2008075213332.hdf using a NCL script

From: Filippo Locci <filippo.locci_at_nyahnyahspammersnyahnyah>
Date: Tue Dec 11 2012 - 09:05:11 MST

Hi,
using examples from http://www.hdfeos.org/zoo/index_openLPDAAC_Examples.php
and modifing a script to open a MYD09GQ file but an error occurs:
fatal:["Execute.c":5773]:variable (YDim) is not in file (eos_file)

My script:

;This example code illustrates how to access and visualize LP_DAAC_MYD Grid
file in NCL.
;If you have any questions, suggestions, comments on this example, please
use the HDF-EOS Forum (http://hdfeos.org/forums).
;If you would like to see an example of any other NASA HDF/HDF-EOS data
product that is not listed in the HDF-EOS Comprehensive Examples page (
http://hdfeos.org/zoo),
;feel free to contact us at eoshelp@hdfgroup.org or post it at the HDF-EOS
Forum (http://hdfeos.org/forums).

load "$NCARG_ROOT/lib/ncarg/nclex/gsun/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

; This is an example of a 2-D grid file data field.
; It is assumed users know how to obtain information such as _FillValue
from HDFView.
; For information about HDFView, visit
http://www.hdfgroup.org/hdf-java-html/hdfview/.

begin

  eos_file=addfile("MYD09GQ.A2006060.h25v06.005.2008075213332.hdf", "r") ;
Read file.
; he2_file = addfile("MYD09A1.A2007273.h03v07.005.2007285103507.hdf.he2",
"r") ; Read file for the second time to efficiently obtain lat and lon.

; List available fields and attributes.
 print(eos_file)

; read data field
  data_raw = eos_file->sur_refl_b01_1

; print(data_raw)

; Apply scale factor according to the field attribute
; correct_data_value = (raw_data_value - offset) * scale_factor
  data = (data_raw - data_raw@add_offset) * data_raw@scale_factor

  data@_FillValue = (data_raw@_FillValue - data_raw@add_offset) *
data_raw@scale_factor

  data@long_name = data_raw@long_name
  data@units = data_raw@units

; Associate longitude and latitude
; data@lat2d=he2_file->GridLat_MOD_Grid_500m_Surface_Reflectance
; data@lon2d=he2_file->GridLon_MOD_Grid_500m_Surface_Reflectance

lat=eos_file->YDim ; associate longitude and latitude
lon=eos_file->XDim ;
lat@_FillValue=-999.0
lon@_FillValue=-999.0

data@lat2d=lat
data@lon2d=lon

  xwks=gsn_open_wks("pdf","MYD09GQ.A2006060.h25v06.005.2008075213332.hdf_sur_refl.ncl")
; open workstation

  res=True ; plot mods desired
  res@cnFillOn=True ; enable contour fill
  res@gsnMaximize=True; make plot large
  res@gsnPaperOrientation = "portrait" ; force portrait orientation
  res@cnLinesOn=False ; turn off contour lines
  res@cnLineLabelsOn = False; turn off contour line labels
  res@gsnSpreadColors = True ; use the entire color spectrum
  res@cnFillMode = "RasterFill" ; faster
  res@lbOrientation ="vertical" ;vertical labels
  res@cnMissingValFillPattern = 0 ; missing value pattern is set to
"SolidFill"
  res@cnMissingValFillColor = 0; white color for missing values

  ; the following 5 sentences are used to create a zoomed image
  res@mpLimitMode = "LatLon"
  res@mpMinLatF = min(data@lat2d) ; Set limits of map, based on the min/max
of the dataset latitude/longitude
  res@mpMaxLatF = max(data@lat2d) ;
  res@mpMinLonF = min(data@lon2d) ;
  res@mpMaxLonF = max(data@lon2d) ;

  gsn_define_colormap(xwks,"BlAqGrYeOrReVi200") ; choose colormap
  res@tiMainString = "MYD09GQ.A2006060.h25v06.005.2008075213332.hdf" ;
create title
  res@gsnLeftString = "Field name: " + data@long_name
  res@gsnRightString = "Units: " + data@units

  plot=gsn_csm_contour_map_ce(xwks,data,res) ; create plot

; cleaning up used resources
  delete(plot)
  delete(res)
  delete(xwks)
  delete(data)
  delete(data_raw)
  delete(eos_file)
; delete(he2_file)

end

I haven't a file where I could read the geolocation. It's possible to read
this file via HDF viewer but
I'm not able to open this file via an NCL script.
Please, give me a suggestion.
Thank you
F

-- 
*Filippo Locci*
*PhD Student*
International PhD in
Environmental Science and Engineering
University of Cagliari
Tel. +390706757701
Mob. +393471372292

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Received on Wed Dec 12 01:05:26 2012

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