Changes between Version 8 and Version 9 of Processing/Wavelengths


Ignore:
Timestamp:
Aug 24, 2017 3:36:18 PM (2 years ago)
Author:
dac
Comment:

Added info about using ENVI header with newer tools

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  • Processing/Wavelengths

    v8 v9  
    11= Sensor band information =
     2
     3== From ENVI header ==
     4
     5The centre wavelength and bandwith for hyperspectral data such as Eagle, Hawk, Fenix and Owl are stored within the ENVI header (.hdr) file associated with each binary (.bil) file.
     6 
     7ENVI header files are plan text files and can be opened in any text editor such as [https://en.wikipedia.org/wiki/Microsoft_Notepad notepad].
     8
     9NERC-ARF also make a selection of tools available for extracting data from header files through https://github.com/pmlrsg/arsf_tools
     10
     11To extract the wavelength of each band to a CSV file the following can be used:
     12
     13{{{
     14get_info_from_header.py f166011b.bil.hdr -o f166011b_wavelengths.csv
     15}}}
     16
     17Within Python you can use:
     18
     19{{{#!python
     20# Import envi_header module
     21from arsf_envi_reader import envi_header
     22
     23# Read the header to a dictonary
     24header_dict = envi_header.read_hdr_file("f166011b.bil.hdr")
     25
     26# Extract wavelengths, splitting into a list
     27wavelengths = header_dict['wavelength'].split(',')
     28
     29# Convert from string to float (optional)   
     30wavelengths = [float(l) for l in wavelengths]                               
     31}}}
     32
     33== Using azgcor (for older data only) ==
     34
     35'''Note azgcor is no longer supplied or supported by NERC-ARF, please contact us if you wish to use folder data in HDF format.'''
    236
    337You can get the bandwidth information from an HDF files by running azexhdf on it.  The information is stored in several vectors in the HDF.
     
    1448The ATM vectors will never vary.  You can use the CSV file at the bottom of this page for ATM.
    1549
    16 == Example commands ==
     50=== Example commands ===
    1751
    1852General form: