Nicolas wrote: > Hello > > a VERY specific question, but I thought someone in the list might have > used this dataset before and could give me some advice > > I am trying to read the daily Antarctic Sea Ice Concentrations from > Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data, as provided by > the national snow and ice data center (http://nsidc.org), more > specifically, these are the files as downloaded from their ftp site > (ftp://sidads.colorado.edu/pub/DATASETS/seaice/polar-stereo/nasateam/final-gsfc/south/daily) > > they are provided in binary files (e.g. nt_19980101_f13_v01_s.bin for > the 1st of Jan. 1998) > > the metadata information > (http://nsidc.org/cgi-bin/get_metadata.pl?id=nsidc-0051) gives the > following information (for the polar stereographic projection): > """ > Data are scaled and stored as one-byte integers in flat binary arrays > > geographical coordinates > N: 90° S: 30.98° E: 180° W: -180° > > Latitude Resolution: 25 km > Longitude Resolution: 25 km > > Distribution Size: 105212 bytes per southern file > """ > > I am unfamiliar with non self-documented files (used to hdf and netcdf > !) and struggle to make sense of how to read these files and plot the > corresponding maps, I've tried using the array module and the > fromstring function > > file=open(filename,'rb') > a=array.array('B',file.read()) > var=numpy.fromstring(a,dtype=np.int) > Try
numpy.fromfile(f, dtype=np.int8) or uint8, depending on whether the data is signed or not. What you did is also correct except that the final dtype must be np.int8. (You can always do var = var.astype(np.int) *afterwards* to convert to a bigger integer type.) Dag Sverre _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
