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MGH_NORM_COORD

MGH_NORM_COORD

Name


  MGH_NORM_COORD

Purpose



  This is my version of the IDL NORM_COORD function (in the
  'examples/objects' subdirectory), with an optional second
  argument, renamed to avoid confusion.
  This is a utility routine to calculate the scaling vector required
  to map a specified range into normalised coordinates. The scaling
  vector is given as a two-element array like this:
    scalingVector = [translationFactor, scalingFactor]
  The scaling vector should be used with the [XYZ]COORD_CONV
  keywords of a graphics object or model. For example, if you wanted
  to scale an X axis into the range [-0.5,0.5], you would use:
    xAxis->GetProperty, CRANGE=xrange
    xAxis->SetProperty, COORD_CONV=MGH_NORM_COORD(xrange, [-0.5, 0.5])
  Note that we have retrieved the CRANGE property of the axis,
  rather than the RANGE property, to get the actual range. Then, to
  calculate the position in normalised coordinates of a data point x
  associated with this axis:
    xAxis->GetProperty, COORD_CONV=xcoord_conv
    xnorm = xcoord_conv[0] + xcoord_conv[1]*x

Category


  Object Graphics.
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  This software is provided subject to the following conditions:
  1. NIWA makes no representations or warranties regarding the
    accuracy of the software, the use to which the software may
    be put or the results to be obtained from the use of the
    software. Accordingly NIWA accepts no liability for any loss
    or damage (whether direct of indirect) incurred by any person
    through the use of or reliance on the software.
  2. NIWA is to be acknowledged as the original author of the
    software where the software is used or presented in any form.
###########################################################################

Modification History


  Mark Hadfield, 1998-03:
    Written.
  Mark Hadfield, 2004-11:
    Now returns a DOUBLE value if either of the inputs is DOUBLE, otherwise
    FLOAT.
  Mark Hadfield, 200?-??:
    Now returns a DOUBLE value in all cases.



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