- Background
  - NeXtMidas is not and does not wish to be a GIS (Geographic Information Service) application.
    - Maps and imagery provide a context for other data being plotted.
    - No support for imagery analysis.
  - A brief history of maps and imagery in NeXtMidas:
    Pre 2004 - "The Dark Ages"
      The only maps available were Type 1999 files (like `world.prm`).
      When the user zoomed in they got the infamous "black screen of death" and lost their bearings. (This can still be seen when running `XGEOPLOT` in X-Midas.)
    2004 - MAP Option Tree
      Directly plots various NGA map and image formats.
      Uses the OpenMap libraries for reading the files, but plots them in the NeXtMidas `PLOT`.
      Problem - Need full set of NGA data on local disk or over NFS.
    2005 - LayerGMap
      Added a NeXtMidas client for the GoogleMaps service.
      Advantage - Can plot maps without local copy of data.
      Problem - Requires internet connection, Google-owned server, server software not available for purchase (as of 2006).
    2006 - LayerNMS
      A two-week effort to build and install a prototype system, called NeXtEarth, that would provide a client-server architecture similar to GoogleMaps but using the MAP option tree for the server.
      Advantage - Have "ownership" of the server installation.
      Problem - Custom protocol, limited feature set.
    2007 - LayerWMS
      Uses the industry-standard OpenGIS Web Map Service (WMS) protocol.
      NeXtMidas client can connect to any number of third-party servers.
      Advantage - Industry standard, supported by many organizations, COTS and GOTS servers available.