2 messages.---------------------------------Johnnie
 
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>Date: Wed, 17 Apr 1996 11:05:57 -0400 (EDT)
>From: Tobias Ullman <[log in to unmask]>
>Subject: Re: Using federal CD-ROM map products
 
 
 
 
On Tue, 16 Apr 1996, William Barrow wrote:
> ----------------------------Original message----------------------------
> Hello,
>   A few weeks ago a query was made to this list, concerning the
> U.S.G.S. Digital Raster Graphics CD-ROMs and how much luck
> people were having in using them.  Other than a comment about
> using 32-bit systems,    nothing was said on-line in response.
- cut-
 
We have looked at both DOD's and DRG's downloadable from the Internet
from the San Fransisco Bay Area Site, using my MAC which I find somewhat
easier than my Pentium.
 
-cut-
 
> Perhaps most institutions either have not ordered the DRGs, or
> haven't yet tried to look at them, but I suspect someone out
> there has been working with them and I would still like to hear
> about their experiences.... particularly under Windows.
 
The following response is not a "Windows" experience, but some
things will apply.
 
>   One aspect of this that concerns me is that we may be adding
> another barrier between the data and the "average" user.  While it
> is true that the paper topographical maps take some familiarization
> before they can be readily comprehended, that is still the case
> with the DRGs.  Now, however, we have the added problem of electronic
> access, with the need for adequate hardware, software and training
> to even SEE the topos in the first place.  High-tech research libraries
- more concerns cut -
 
Most graphics programs easily import such files now (both DOQ & DRG) and
they can be far more "user" friendly than the typical GIS.  The catch
being to display the map to scale.  However this problem has recently
been solved through the use of an image registration filter provided
within the MAPublisher plug-in that works with Adobe Illustrator. From
Adobe Illustrator you can easily output postscript files for printing.
 
The caveat being that these files when uncompressed can be really huge.
The ones I downloaded were 30-70 MGs each!  Even with a Power Mac, the
import time can be slow.  You can run them through something like
Photoshop first to reduce the resolution and so the file size.  This
is a reasonable solution with the DOQ's depending on the scale you
want to use for viewing and printing/plotting.  However the DRG's
do not reduce as well, too much detail seems to be lost.  Again this
would be dependent on your end use for the digital product.
 
Raster images with current technology certainly do have limitations
when it comes to speed of import and viewing.  However as we all are
aware this technology is improving rapidly, so that these known
problems should be addressed eventually.  The plus side is the
potential for storing and reproducing at will, which is why many
goverment agencies and others are scanning in all their maps for
archival and later reproduction.
 
>   We've all said and heard that the digital revolution was going to
> bring both wonderful new means of access and troubling new problems to
> solve.  Well, how are we going to solve the issue of acquiring the
> technical expertise to access and use the digital products coming out?
> Attend a two-hour workshop once a year at an ALA or SLA meeting in
> Hawaii?  Read the sparce documentation? Or go back and get another
> masters degree, in geography or computer science?
 
The available graphics software such as Adobe Illustrator, Macromedia's
Freehand, etc. do provide a more user friendly and less high tech avenue
for viewing and printing such imagery.  Our company is slated to have
two workshops (one PC and one MAC) this fall at the NACIS show in San
Antonio this fall.  For anyone who plans to be there it will be an
opportunity to see how easy the graphics world can make the life of the
mapmakers.
 
Hope this answers some of your questions.
 
> I, for one, would be an eager reader, and I can think of several others
> who probably would be, too.
>
> Bill Barrow
 
************************************************************
Denise Ullman                     [log in to unmask]
Product Development Manager
Avenza Software                 http://www.avenza.com
Developers of MAPublisher - changing the way maps are made.
Telephone: 1-905-639-3330 or 1-800-884-2555 (Canada Only)
************************************************************
 
 
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>From: [log in to unmask]
>Date: Wed, 17 Apr 96 12:26:55 PST
>Subject: Re: Using federal CD-ROM map products (fwd)
 
 
     Bill,
 
     We just received the DRG-Capital cities of the U.S. cd-rom. This cd
     contains *.tif files which are approx. 12Mb in size, but the data is
     compressed. When each quad is unpacked the file size is over 42Mb. So
     you need a fairly good PC to handle this amount of data. We are using
     a Pentium 90Mhz with 32Mb RAM, Windows 3.1 and ArcView 2.0. The DRGs
     open up OK, but the quality is poor until you zoom in. Displaying and
     panning around the image is a bit slow due to the file size, but under
     1 minute. Since I have ArcView ver. 2.0, I have not tried the viewing
     software contained on the CD.
 
     In general I agree with you that many of the Depository CDs are not an
     easy fix to paper maps. The Landview II for selected EPA site, for
     example, took over 40 minutes to display one image on the same PC.
     That one goes on a back shelf! So far I have not figured out what
     software will display the DOQs. It's getting hard to keep up.
 
     John Creaser
     Earth Sciences & Map Library
     University of Californioa - Berkeley