The US Geological Survey (USGS) and the Association of American State Geologists (AASG) have worked together to build the National Geologic Map Database (NGMDB).  The NGMDB is mandated to be a standardized, “national archive” of geoscience information (maps and reports, both published and unpublished), made available to the public to support decision-making, research, and other needs. Its website opened in 1996, and it currently serves about 60,000 users each month, who make about 220,000 visits.

The principal sections of the NGMDB are: Continue reading →

Check out this essay comparing the cartography between Google Maps and Apple Maps.  In summary:

• Apple Maps, on average, labels more cities than Google at every zoom.
• Google Maps, on average, labels more roads than Apple on nearly every zoom.
• For two-thirds of zooms, both maps generally show the same number of roads. For the remaining third, Apple shows more roads.
• Both maps, on average, label a similar number of Points of Interest (POIs) — but have only 10% of their POIs in common on an average zoom.
• Both maps also prioritize different kinds of POIs: Google Maps heavily prioritizes transit, while Apple prioritizes landmarks. Apple also generally shows a greater number of POI categories on a given zoom — and shows twice as many restaurants and shops as Google.

Continue reading →

Trying to find that perfect color palette for your choropleth map?  Check out this posting about using the right tool to choose that perfect set of colors for data visualization.