This unit consists of a variety of materials that explain the shape of the Earth and how it is measured. There is a set of 'proofs' that the Earth is round, an account of how Greek geographer and mathematician...

A Dynamic Digital Map (DDM) is a stand-alone program that displays and links maps, images, movies, data and text, such as map explanations and field trip guides. DDMs appear as thematic maps containing camera icons and...

This collection of historic topographic maps goes back to the late 19th century. Comparison of maps of the same area from different times allows users to observe changes in land use over time. The maps can be searched by...

This online exhibit features a selection of various types of maps from the collections of the Library of Congress and the American Congress on Surveying and Mapping (ACSM). Map types include survey maps such as the...

Many people have fond memories of the special maps created as inserts placed in the National Geographic magazine from time to time. This rather special section of the National Geographic's website provides interested...