Dion,
While I see that you've received a few replies on your topo map question,
here's some more information.
We maintain a web site for exchange (one for one) and sale of USGS Digital
Raster Graphic (DRG) topographic maps. The site URL is:
www.pipeline.com/~jcsi-maps/drgs
DRGs come on CD-ROM, with the normal coverage area (per CD) being one
degree (latitude and longitude). For a "normal" inland area, this equates
to one 1:250,000 scale map, two 1:100,000 scale maps, and 64 1:24,000 scale
maps. Our DRG CDs are the standard USGS format, and include the "world"
(*.tfw) file for georeferencing and the metadata file (*.fgd) for each map.
The maps themselves are TIF images; most (except for those in TVA or
California Teale Data Center areas) are geotiffs, which carry embedded
"tags" for geoferencing. Either the world file or the geotiff tag can be
used with MapInfo to correctly place the images. These maps are not
copyrighted by the USGS. Unlike Suremaps or commercial derivatives, there
are no potential copyright issues involved in using the maps in reports or
other products.
There is considerably more technical information about DRGs on the web
site, as well as coverage maps of what we currently have on hand. If you
have no DRGs to trade, you can purchase them; the prices start at $30 each
per degree square for the first three, $25 each for the next three, and $20
each for any that you order after the first six. We are also set up to
bulk orders quickly. Please e-mail me if you have any questions about DRGs.
Mike Jenne
JCSI
At 05:18 PM 7/19/99 -0700, Dion Duran wrote:
>To All,
> Where can I get digital topo maps for the US? Currently I order
>paper maps from the USGS and scan them in on a B&W large format scanner. I
>looked at Sure!Maps. Any other suggestions. Basically I use them for
>elevation analysis, but more importantly I can see more detail about area
>landscape than with just plain TIGER data like parks and buildings. I've
>used DEM files before for elevation. I'm really looking for a replacement
>for the topos. What else is there?
>
>Thanks,
>Dion Duran
>GIS Systems Analyst
>GIS - Houston
>Metricom, Inc.
>[EMAIL PROTECTED]
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