Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!purdue!decwrl!shelby!Portia!hanauma!rick From: rick@hanauma (Richard Ottolini) Newsgroups: comp.graphics Subject: Re: Geographics Informations Systems Message-ID: <1997@Portia.Stanford.EDU> Date: 2 May 89 17:49:01 GMT Sender: USENET News System Reply-To: rick@hanauma (Richard Ottolini) Organization: Stanford University, Dept. of Geophysics Lines: 30 Many commerical and non-commercial groups are working on this problem. Among the furthest along and most public, although not highest tech, is the United States Geologic Survey. Some issues: (1) The input problem: The USGS is committed to a decade long project to enter its topo maps into the computer. They are digitizing the originals--- about a dozen mylar layers per map each representing a feature: water, buildingds, contours, etc. Vector-extraction is semi-automatic; there are confusing features either due to complex geographies or original error requiring human intervention and expert system resolution. (2) The memory storage problem: I heard an estimate of ten terrabytes for for the 55K USGS map collection. And this is relatively coarse vector information. By the time the topo maps are digitized, ten terrabyte optical systems should be available. (3) The information representation problem: The USGS data is stored as vector sets in approximate location order. There is minimal feature naming or indexing. This fine for drawing maps, but difficult for locating named features or constructing roadmaps, etc. It is the classical database problem of efficiency verses functionality, but on a huge scale. (4) The copyright problem: When efficient GIS's become available, the databases themselves become exetremely valuable and some commercial mechanism will have to be found to distribute them. (5) The display problem: Maps require large, high resolution screen or printed displays. They need good interfaces, either interactive or well thought out artistry, to mange the complexity of information. I believe this problem is closest to a solution in both its traditional printed maps and computer interfaces. Some GISs are IMAGE-oriented or combined image and vector representations, derived from airplane and satellite images. They share, if not increase, the above problems.