>  Docs Center  >  Libraries  >  Coyote  >  SCALEMODIS

SCALEMODIS

SCALEMODIS

Name


  SCALEMODIS

Purpose



  MODIS corrected reflectance images often appear drab when initially processed
  and displayed on a computer using BYTSCL. In fact, the resulting true-color
  images look nothing like the images you can find on the MODIS Rapid Response
  web page (http://rapidfire.sci.gsfc.nasa.gov/gallery/). After poking around on
  the Internet for awhile, I discovered that the Rapid Response Team doesn't use
  BYTSCL to prepare the images. Rather, they selectively scale portions of the
  reflectance image, using a piecewise scaling with different slopes. This program
  implements this Rapid Response Team algorithm.

Author



  FANNING SOFTWARE CONSULTING
  David Fanning, Ph.D.
  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/

Category



  Graphics

Calling Sequence



  scaledBand = ScaleModis(red, green, blue)

Arguments



  red: A two-dimensional array representing the corrected reflectance
                values of a MODIS image. This is a required parameter. If the
                green and blue parameters are also used, this parameter will
                represent the red band of a RGB 24-bit scaled image that is returned.
               
  green: If the three parameters--red, green, and blue--are present, the returned
                array is a 24-bit true-color image, scaled appropriately. This parameter
                is used as the green band in such an image. The parameter is a two-dimensional
                array of corrected reflectance values.
           
  blue: If the three parameters--red, green, and blue--are present, the returned
                array is a 24-bit true-color image, scaled appropriately. This parameter
                is used as the blue band in such an image. The parameter is a two-dimensional
                array of corrected reflectance values.
               

Keyword Parameters



  RANGE: A two-dimensional array that the input bands are first scaled into, prior to
                the differential scaling using the MODIS Rapid Response algorithm. The default
                input range is [-0.01, 1.10]. These values will be used to set the MIN and MAX
                keywords for the BYTSCL command in the initial scaling of the input bands.
  CLOUD: The MODIS Rapid Response team uses a slightly different scaling algorithm when
                the idea is to emphasize clouds in a MODIS scene. Set this keyword to use the
                alternate cloud scaling algorithm.

Outputs


 
  scaledBand: If a single 2D array is passed as the argument, then scaledBand is the scaled
                2D output array. If all three arguments are passed to the program, then scaledBand
                is a scaled 24-bit image that represents a true-color or false color representation
                of the three input bands.
               

Modification History



  Written by: David W. Fanning, July 2009, using the IDL programs MODIS_FALSE_COLOR and
    and SCALE_IMAGE for inspiration. I found these programs on the Internet when poking
    around MODIS web pages. I suspect, but I am not sure, these programs were originally
    written by Liam Gumley.
  Minor changes to the ScaleIt function to be sure partitioning is done correctly. 5 Aug 2009. DWF.



© 2019 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us