With the UT-Bureau Of Economic Geology’s Scale Calculator, enter a map scale and it calculates what a measurement on the map represents in reality, or what a unit distance translates to at that map scale:
There are also links at the top of the page to other calculators for area/distance conversion, and decimal degree / deg-min-sec degree conversions (both ways).
The OSU Scale Calculator is a bit different – enter a map measurement distance for a unit distance, and get back the map scale number:
There’s also another calculator for basic distance unit conversions, plus also conversions from degrees of slope to % grade and back:
Via Kelso’s Corner (which also has some useful tables and info related to map scale),
The AfricaMap website from Harvard University offers dozens of vector and raster datasets that you can display inside of a Google Maps interface. Data categories include geographic, political, economic, environmental, linguistic, ethnic, historic and more. Most of the datasets can also be download in GIS-compatible formats, with a fair number also available in Google Earth KMZ format (indicated by a “3D” link in the data listing). Here’s a display of African language families from 2001, for which you can also download the original shapefile data:
Zooming in will display labels, but you can also bring up a pop-up window with the map legend inside.
There’s also a “Places” tab that lets you plot point geographic locations for cities, lakes, canals, marshes, mountains, plateaus, and many more. Here’s a plot of gorges in Africa:
Zoom in closer to an area:
Click nearby a plotted location, and get a pop-up window with more information on the feature:
