Digitized Terrain Models

[Bruce Karsh]

In article <8808171454.aa08382 at AMSAA-SEER.AMSAA-SEER.ARPA> dhanson at AMSAA-SEER.ARPA (Del Hanson, AWD) writes:
>I am looking for any models which can be used to display digitized 
>terrain data on a 4D/60T.

Here is a posting from a few months ago from comp.graphics that might be
of interest to digital terrain fans:

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>From sgi!decwrl!ucbvax!agate!helios.ee.lbl.gov!lll-tis!oodis01!uplherc!utah-gr!utah-cs!crum Wed Jun  1 18:38:09 PDT 1988
Article 2691 of comp.graphics:
Path: sgi!decwrl!ucbvax!agate!helios.ee.lbl.gov!lll-tis!oodis01!uplherc!utah-gr!utah-cs!crum
>From: crum at utah-cs.UUCP (Gary L. Crum)
Newsgroups: comp.graphics
Subject: machine-readable maps
Summary: Internet archive for digital maps started.
Keywords: map cartography USGS DEM
Message-ID: <5520 at utah-cs.UUCP>
Date: 26 May 88 18:14:22 GMT
Organization: University of Utah CS Dept
Lines: 54

The National Cartographic Information Center (NCIC) distributes digital
cartographic/geographic data files produced by the U.S. Geological Survey
(USGS) as part of the National Mapping Program.  I have purchased one
of the maps and I am making it available by anonymous ftp from Internet
host wasatch.utah.edu in the directory pub/maps/dem.  That directory contains:

-rw-r--r--  1 crum          256 May 26 11:21 INDEX
-rw-r--r--  1 crum      1090600 May 26 10:33 MAP.N0009338
-rw-r--r--  1 crum       278140 May 26 12:03 MAP.N0009338.Z
-rw-r--r--  1 crum         1481 May 26 11:37 README

where MAP.N0009338 is DEM data for the quadrant where I am posting from.

Applications of computers to provide dynamic perspective viewing of 3D
geographic-scale data models sounds interesting and is becoming practical
with the availability of transformation hardware.  One such viewing
program is a class project of mine this quarter.

Please contribute machine-readable geographic data to my collection as
suggested by my README file included below.  Thanks,  -Gary (crum at cs.utah.edu)

--- README from ~ftp/pub/maps/dem on wasatch.utah.edu ---

This directory contains Digital Elevation Model data as made available
by the United States Geological Survey National Mapping Program.

The format of DEM map files is described in the publication "Digital
Elevation Models, Data Users Guide" available free of charge from:

>	 National Cartographic Information Center
>	 U. S. Geological Survey
>	 507 National Center
>	 Reston, VA  22092

	(703)860-6045

DEM tapes for 7.5 minute square quadrants cost $100 plus a $25 service charge.
This data was obtained by Gary Crum at the University of Utah, and it is
being made publicly available because it is not copyrighted and in hopes
that others who have purchased DEM data will make their data available here.
The USGS distribution charge is very high, considering that 100 DEM quads
would fit on a single 2400' 6250bpi tape, but such a tape would cost around
100 * $100 = $10,000 plus the $25 per tape service charge.

DEM maps in this directory are described in the INDEX file.
If you would like to help offset the cost of purchasing map data from
USGS, please send a contribution to the corresponding buyers listed in
the INDEX file.  $5 per map seems reasonable.

Thank you.  This DEM data is (as of 25-May-1988) available by anonymous
ftp from Internet host wasatch.utah.edu in the directory pub/maps/dem.
If you can contribute map data, please do by transferring map datafiles to
this writable directory and requesting that the INDEX file be updated by
the maintainer, crum at wasatch.utah.edu.

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--
			Bruce Karsh
			karsh at sgi.com

Every time I bite my tongue, "Mr. Palomar concludes mentally,
"I must think not only of what I am about to say or not say, but
also of everything that, whether I say it or do not say it, will be
said or not said by me or by others."

--
			Bruce Karsh
			karsh at sgi.com

Every time I bite my tongue, "Mr. Palomar concludes mentally,
"I must think not only of what I am about to say or not say, but
also of everything that, whether I say it or do not say it, will be
said or not said by me or by others."