Earthdata Forum

Dear Sir or Madam,

Hope this email do not make any inconvenience. I send this email to ask if there any public software or program utilities to help users to read "Topex Altimeter Sensor Data Record" dataset in raw format. I have downloaded two files and both of them are with file extension ".dat". However, when I try to read them with python, it seems that this dataset is coded with "ISO 646-1983" (from documentation https://archive.podaac.earthdata.nasa.gov/podaac-ops-cumulus-docs/topex/open/L1B/altsdr/docs/D-8591_C_sdr.pdf), which does not listed in supported encoding types in Python (https://docs.python.org/3.12/library/codecs.html#standard-encodings) and other commonplace computer languages.

I want to retrack waveforms in this dataset for specific use. I would appreciate it if anyone can give me some hints about this.

Cheers,
Jianwei Luo

Hi Jianwei,

Please see the matlab script linked here: https://podaac.jpl.nasa.gov/dataset/TOPEX_ALTSDR#faceted-browse-documentation It shows how to read the .dat files. I just tested it locally and read a random file into memory successfully.

If you're using python, you should be able to read the headers as plain ascii text and the binary data according to the byte offsets noted in the pdf and matlab script. (The latter should be very helpful.)

Please let us know how it goes. Thanks!
Jack @ PODAAC