Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!batcomputer!eric
From: eric@batcomputer.tn.cornell.edu (Eric Fielding)
Newsgroups: comp.graphics
Subject: Re: GIS systems
Message-ID: <7949@batcomputer.tn.cornell.edu>
Date: 15 May 89 16:12:12 GMT
Reply-To: fielding@geology.tn.cornell.edu
Distribution: na
Organization: Department of Geological Sciences, Cornell University
Lines: 26

In a recent article rick@hanauma (Richard Ottolini) wrote:
>....  Just wait until airplane or satellite image data is incorporated
>as the USGS plans to do and military mapping agencies are already attempting!
>3000 EW km x 10 pixels / km x 1500 NS km x 10 x 10 spectral bands x 1 byte / band
>equals 450 GB.
(this does not multiply out right on my calculator. I get 4.5 GB.)

10 pixels per km is pretty low resolution. The Landsat Thematic Mapper data 
(with complete coverage of the US several times over) has 30 m pixels and
seven bands:  3000 km x 30 p/km x 1500 km x 30 x 7 bands = 28 GB.

There is the SPOT imagery 10 m resolution x 1 spectral band = 450 GB
I believe this is available for the full US several times over, also.

Then there is the Eos (Earth Observing System) NASA is planning to launch in 
the mid-90s. It will have an instrument call HIRIS with 30 m pixels and 
up to 128 bands (limited by the rate at which they can beam it down), with
a 30 km wide swath. This should cover the US several times a year. They are
now trying to figure out how to deal with this data volume.

			++Eric Fielding
fielding@geology.tn.cornell.edu

(BTW, I analyzed about 2.5 GB of Landsat Thematic Mapper data for my PhD
dissertation. The new digital videotape storage devices make this pretty
easy.)