Interactive cartography

The authors present a software program that allows users to interactively create different map projections. The system allows users to view a representation of the Earth simultaneously as a sphere and as a projection with the ability to interact with both images. Map projections are created by projecting the sphere onto one of three developable surfaces. The choices are a cylinder, cone, or a plane. The surface can then be manipulated interactively e.g. orientation, size, distance, adjust central meridian, etc. to instantly create the corresponding map projection. The projection calculations take advantage of the GCTPC package provided by the USGS. Their implementation is written in C++ and uses OpenGL for the graphics rendering. The graphical user interface is built using FLTK. This software has been tested on SGIs and SUNs running Unix and PCs running both Linux and NT. Software as well as additional information are available from www.cse.ucsc.edu/research/avis/map.html