----------------------------Original message----------------------------
Raster base images of maps can be of great use in georeferencing if
UTM or lat/long coordinates of the image are given. In the case of topo
maps those points are already there. The primary problem is file size vs.
image resolution and working on a computer with enough horse power as to
not wait for image redraws. Another problem is good quality, hard copy
output.
 
I am looking forward to getting a set of those  CD's as it will save a
step for the students/faculty and clients who come to our lab to have
maps scanned in order to trace off or add information to those sections
of maps.
 
 
Jim Robb
Cartography Lab
Geography Dept., Univ. of Colorado-Boulder
(303)492-5288
 
 
On Sat, 8 Jul 1995, Duane F Marble wrote:
 
> ----------------------------Original message----------------------------
> The Digital Raster Graphics are indeed images and not databases. There
> is nothing that a GIS can do with them other than to use them as a
> backdrop ("wallpaper") for other covers. When I was given one of the
> early demo disks I wondered why USGS was doing this. In response to
> my query on GIS-L I received a long reply from the USGS listing a
> number of reasons all related to internal map production matters. I
> received only one other response from someone who found them useful.
> In that latter case the company had to deal with a state agency (Texas
> as I recall) that required them to submit their permiting requests,
> etc., as overlays to 1:24K quads. CDs are cheap, but this distribution
> still appears to me to be of very limited utility.
>
> --
> Duane F. Marble                E-mail: [log in to unmask]
> Dept. of Geography             Home Page: http://thoth.sbs.ohio-state.edu
> The Ohio State University      Telephone:  (614) 292-2250
> Columbus, OH 43210             Fax:  (614) 292-6213
>