GOM - the Global Overlay Mapping System

The World Map

The World map loads with a single click on the 'World' label in the main toolbar. This map has a different overlay-toolbar from any of the other maps, as it uses different overlays. There was no point trying to squeeze flags, prefixes, city or country names on a map of this scale, so instead some extra, unique overlays were added. Here some notes about all the overlays:

  • Earth - this overlay is created from Nasa's spectacular 'Blue Marble' image, a composite of Land Surface, Shallow Water, and Shaded Topography. It is the most detailed true-color image of the entire Earth to date. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations into a seamless, true-color mosaic of every square kilometer of our planet.
     
  • Relief - this overlay was created using a custom color-file and the GMT software package, from the ETOPO2 - 2 minute Worldwide Bathymetry/Topography dataset. Further information on the ETOPO2 dataset, and the some color relief images, can be found HERE. A key to the colors used in the image can be seen on the Relief Map page.
     
  • Night - this overlay was created from a composite satellite photograph of the world, and clearly shows the actual light radiated from towns and cities all over the planet. The image was created with data from the US Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earth’s surface. The lights, derived from 9 months of observations by the Defense Meteorological Satellite Program, have been superimposed on a darkened land surface map.
     
  • Outlines - the overlays for Time, CQ, and ITU Zones, also Continent, ITU Region and Country Outlines were created from standard data-sources. They can be with whichever background you wish.
     
  • Beacon - this overlay shows the position of the current NCDXF HF Beacons. These useful aids to propagation transmit in a regular cycle on the the following frequencies: 14.100, 18.110, 21.150, 24.930, and 28.200 MHz, and are a useful way of determining which bands are currently open. For further information, visit the International Beacon Project website HERE.
     
  • Grid Loc - further information about Grid Locators can be found HERE.
     
  • LatLon - further information about Latitude and Longitude can be found HERE.