Two messages concerning the EDRISI question.-----------Johnnie ---------------------------------------------- Thu, 27 Jan 94 10:14:30 EST [log in to unmask] (Keith Clarke) Re: EDRISI EDRISI is in fact, IDRISI (named for the Islamic Cartographer). The package is microcomputer based, and was developed at Clark University in the Geography program by J. R. Eastman. There is an Internet support group for IDRISI at [log in to unmask] To subscribe to this list, send a subcribe message to [log in to unmask] I am quoting from Analytical and Computer Cartography, 2nd Ed., Chapter 6 : Access to Spatial Data which I am now finished with and editing to appear in early 1995. Keith Clarke ----------------------------------------------- Thu, 27 Jan 94 09:18:00 EST Blake Gumprecht <GUMPBW@TEMPLEVM> Re: EDRISI IDRISI is a relatively inexpensive (under $500 I've heard) raster-based GIS produced by the geography department at Clark University in Worcester, Mass. I have only limited experiencing using it, so I'm not sure if it will fill the needs of your professors. Raster-based systems are made up of equal size grids, much like your TV screen. As a result, they are rather inprecise and are best used for performing analysis and producing maps for information with imprecise boundaries (trees types, climatic data, etc.). Vector-based systems, which are made up of points, lines and polygons, are much more precise. They are more appropriate if you want to map or analyze socioeconomic data for small areas -- say poverty levels by Census tract. The leading vector-based system is called ARC/INFO, produced by Environmental Systems Research Institute of Redlands, Calif. ARC/INFO is fairly pricey. The same company produces a less expensive and more user-friendly, but also less powerful system called ARC/VIEW. Blake Gumprecht Telephone: (215) 204-3187 Documents Librarian Fax: (215) 204-5201 Paley Library (017-00) Internet: [log in to unmask] Temple University Bitnet: gumpbw@templevm Philadelphia, PA 19122