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  Provides an easy way to set up a map projection coordinate space using GCTP map
  projections normally accessed via Map_Proj_Init. Allows an unlimited number of map
  overlays, and can provide a fresh map structure on demand, eliminating the problem
  of ephemerial map structures that plaqued Map_Proj_Init until IDL 8.x. This program
  is basically a wrapper for Map_Proj_Init, with additional features that make it
  superiour for working with map projections in IDL.


    Graphics, Map Projections
    Only GCTP projections are allowed. If you wish to use projections normally
    set up with Map_Set, use the comparable cgMap_Set command.


    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


    Change History::
        Brought over to the Coyote Library from a similar routine in the Catalyst Library.
          Updated to account for the bug that creates incorrect result in UTM projections
          when using the WGS84 ellipsoid. The Wallbeck ellipsoid is substituted for the
          WGS84 ellipsoid in this instance. David W. Fanning, 7 November 2011.
        Added IS_CYLINDRICAL method to solve a problem with grid labeling and drawing
          of grid lines. 16 Dec 2011. DWF.
        Added ERASE method to erase the display. 28 Dec 2011. DWF.
        Added check for identical range values in FORWARD method. 30 Dec 2011. DWF.
        I am convinced that the map structure returned by Map_Proj_Init, when there
          is a LIMIT used in the call contains a uv_box with incorrect latitude values.
          This is important because other routines (e.g., cgMapGrid) depend on these values.
          I've created a fix wherein, I fixed the uv_box latitude values to correspond
          to the LIMIT of the map projection. 6 April 2012. DWF.
        Set the default CENTER_LATITUDE and CENTER_LONGITUDE to 0.0. 9 April 2012. DWF.
        Added NOFORWARDFIX keyword to allow skipping of the "fix" in the FORWRD method,
          as sometimes this is not needed or required. 29 June 2012. DWF.


    Copyright (c) 2011-2012, Fanning Software Consulting, Inc.

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