Sensor band information

You can get the bandwidth information from an HDF files by running azexhdf on it. The information is stored in several vectors in the HDF.

For CCD sensors, the key vectors are:

• CAwavc: wavelength central frequencies for CCD sensors (CASI, Eagle, Hawk), in nm
• CAwavh: wavelength half bandwidth for CCD sensors (CASI, Eagle, Hawk), in nm

The number of entries in the vectors will vary for CCD sensors depending on the band configuration.

For ATM,

• ATwavu & ATwavl: upper and lower wavelength limits for ATM, in nm

The ATM vectors will never vary. You can use the CSV file at the bottom of this page for ATM.

Example commands

General form:

• azexhdf -vf OUTPUT_FILE.txt -vn VECTOR_NAME -h LEV1_HDF_FILENAME

Example

• azexhdf -vf casi192_wave_centre.txt -vn CAwavc -h lev1/c192a011b.hdf
  • this prints lots of information and also outputs the vector as space-separated numbers to the file, e.g.

     408.94 440.93 488.94 508.72 528.52 559.66 570.06 588.97 620.21 648.68 670.55 679.11 684.83 704.86 754.62 779.60 871.54
    

  • The output is in order of band number.

A unix command to transpose this output into a column is cat OUTPUT_FILE.txt | tr ' ' \\n > OUTPUT_FILE-transposed.txt

---

A Linux script that will produce a CSV file of a CASI, Eagle or Hawk HDF is attached to the bottom of this page.

• Save the script somewhere on a Linux system
• Make the script executable (chmod +x /path/to/create_band_info_csv.sh)
• Run the script: /path/to/create_band_info_csv.sh /another/path/to/level1_HDF_file.hdf /yet/another/path/to/output.csv
  • Note you must have the azexhdf command installed somewhere in the path (ie. such that typing "azexhdf" works).
• If it all runs ok, you should be able to load the csv file into Excel or other spreadsheet packages