Dictionary of Abbreviations and Acronyms in Geographic Information Systems, Cartography, and Remote Sensing (Regents of the University of California) http://www.lib.berkeley.edu/EART/abbrev.html
Gallery of Map Projections: http://www.galleryofmapprojections.com/ (Paul B. Anderson)
Includes maps showing different types of map projections. Also includes publications and presentations by map professionals.
"Geocode any North American location."
How to convert decimal degrees into degrees, minutes, seconds (Matt Rosenberg) http://geography.about.com/c/ht/00/07/How_Convert_Decimal_Degrees0962932697.htm
How to Measure Distances on a Map http://geography.about.com/od/understandmaps/ht/htscale1.htm (Matt Rosenberg)
Isolines: http://geography.about.com/library/misc/blisoline.htm (About.com: geography)
Journal of Spatial Science http://www.mappingsciences.org.au/journal.htm (Mapping Sciences Institute, Australia)
Map History: The History of Cartography http://www.maphistory.info/ (WWW-Virtual Library History)
This site covers journals and newsletters related to the history of cartography.
Mathematical Data for Bibliographic Descriptions of Cartographic Material and Spatial Data :
http://www.kb.nl/skd/mathemat.html (by Jan Smits)
Includes a section on "Petermann's bar scale values" that lists ways of measuring distance by country and gives the metric equivalent.
Mathematics of Cartography: http://math.rice.edu/~lanius/pres/map/ (Cynthia Lanius)
Relief Shading: http://www.reliefshading.com/
Provides information about shaded relief in mapping.
Shaded Relief: http://www.shadedrelief.com/ (Tom Patterson, U.S. National Park Service) Examples, articles and tutorials of shaded relief mapping.
Topographic Map Symbols: http://egsc.usgs.gov/isb/pubs/booklets/symbols/ (U.S. Geological Survey)
Assists in understanding topographic maps.