Description

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  Provides a simple way to obtain the data indices from a Histogram REVERSE_INDICES
  vector. Returns a -1 if no indices are available. Check the COUNT keyword for the
  number of indices returned.

Categories

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    Utilities
   

Params

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    ri: in, required, type=integer
        The REVERSE_INDICES vector that is returned from the HISTOGRAM command.
    index: in, required, type=integer
        The zero-based index into the REVERSE_INDICES vector from which to obtain
        the indices. For example, an index value of 4 will return the indices in
        the 5th bin (zero based counting) of the histogram.
     

Keywords

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    count: out, optional, type=Long
        The number of indices returned by the function.
       

Return Value

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      indices:
        The indices that were put into the indexth bin of the histogram. A -1
        is returned if no indices are in that particular bin.
         

Examples

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    Used with the HISTOGRAM command::
      IDL> image = cgDemoData(7)
      IDL> h = Histogram(image, REVERSE_INDICES=ri)
      IDL> indices = cgReverseIndices(ri, 4, COUNT=cnt)
      IDL> Help, indices, cnt, h[4]
      INDICES LONG = Array[948]
      CNT LONG = 948
      <Expression> LONG = 948
      IDL> image[indices] = 0
     

Author

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      FANNING SOFTWARE CONSULTING::
          David W. Fanning
          1645 Sheely Drive
          Fort Collins, CO 80526 USA
          Phone: 970-221-0438
          E-mail: david@idlcoyote.com
          Coyote's Guide to IDL Programming: http://www.idlcoyote.com

History

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    Written by David W. Fanning at suggestion of Ben Tupper. 7 January 2011.
   

Copyright

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    Copyright (c) 2011, Fanning Software Consulting, Inc.