TODO
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Graphics/user interface:
* Full 3D earth renderer (partially done)
* HUD to display text labels and icons (partially done)
  * Text label support
    * Bar with current geographical coordinates and statistics
    * Freetype font renderer (will also allow internationalization
      of HUD)
* GUI (most probably Qt)
* Ability to set initial viewer's coordinates, possibly with location
  catalogue (patch available)
* gaia-mkmap utility; tell it corner coordinates, dimensions, dpi, and
  it'll make you map in single JPEG, ready for printing or whatever.
  (should be also available from gaia itself). XXX: wtf is geotiffs?
* Implement non-realtime OpenGL rendering. Thus, even software
  emulation will be usable. You navigate with only hollow grid
  visible, then you stop navigating and the view is rendered in 3D.
  Anyone can tell me, is software OpenGL available in Windows Mobile
  devices?

Caching:
* Implement tile cache. It'll be compatible with NASA layer, but
  generally multi-purpose.
* Add utility to control it (read and write dumps, read and write
  separate files, delete areas etc.).

Slave layers:
* GPS: Render path in lines, instead of HUD dots
* GPS: Path optimizer (convert strait line of points to 2 points)
* GPS: Interface to add muliple GPS entities from command line
* GPS: Auto reconnect to gpsd if connection is lost
* GPS: Direction indicator for easy finding marker that's not in view
  currently.
* GPS: Ability to follow GPS marker
* Grid: correct grid rendering
  * Render degrees for grid lines (via HUD)
* Anyone with any good layer ideas? Mail me (working layers are most
  welcome, of course:)
  * My ideas so far: SunlightLayer, TimezoneLayer,
    SatelliteCoverageLayer
* Layer to place and display any number of custom image files on
  the map. Will add support for these:
  http://www.archive.org/details/maps_usgs
  Most probably, that'll be available only ofter GUI is done, it's
  to clumsy to control from command line.
* Country borders (patch avilable)

Other:
* Windows port

Random ideas and suggestions (for far future):
* GIS support (grass.itc.it, qgis.org), export geotiffs (what's that?)
* www.ecogeographica.com support (didn't looked there yet)
* Add list of contributors

Known bugs:
* Tile may be loaded twice (master layer refactoring)
* Tiles are sometimes stuck unloaded (master layer refactoring)
* Timer is not threadsafe
* On MacOSX, when exiting, stucks on pthread_join in
  SimpleTileStorage::~SimpleTileStorage (I suppose it will stuck on
  any pthread_join, as thread handling is the same everywhere in gaia).
* NMEA doesn't work with USB devices on Linux (putc to a clist with no
  reserved cblocks). Also need to setup tty before work (like line
  speed etc.)