[meteorite-list] Basic Map and Other Research was "Southwest Impact Study photos"

From: Paul Heinrich <lenticulina1_at_meteoritecentral.com>
Date: Thu Apr 22 10:25:35 2004
Message-ID: <20030506015316.30623.qmail_at_web21409.mail.yahoo.com>

On Mon, 5 May 2003 14:49:44 -0600
Matt Morgan wrote:

>Where is it? I will see if I have it.

>Mark Jackson wrote:

>>There is no geologic map of this area.
>>I've been looking for body of knowledge,
>>theses, maps ANYTHING to help. There
>>is nothing. I am writing the book
>>apparently.

In 99 percent of the time, "writing book" is
simply the case. Just about everywhere in the
US has some sort of geologic mapping at
some scale and with varying degrees of
details available for it. It is a matter of knowing
how to find it and obtain the actual map or a
copy of it. At this time, the big picture for the
majority of the United States in known. In cases,
it is only the details, e.g., the 1:24,000 scale,
is not known. Of course the devil can be in
the details, but that is another matter.

The very basic steps a person needs to do are:

1. Visit your local college / university library
and ask the librarian, if they have the GEOREF
geologic database. If they have it and allow
patrons to use it. Do keyword searches by
county and any other geographic keyword that
describes your location.

2. Use the citations, which will include many
geologic maps, to look for additional sources of
geologic maps, published and unpublished and
other citations that have fallen through the cracks
in the ongoing compilation of the GEOREF
database.

3. Get a list of publications from your local geologic
survey. Look at the publications and maps that they
have for sale. All geologic surveys have state
geologic maps and regional geologic maps
covering the entire state. Even thought they might
not show small features, they provide an overview
of regional geology to give a person a basic
understanding of the regional geology. Also, many
surveys maintain indexes of all geologic mapping
done in the state. For example, in case of
California go look at:

http://www.consrv.ca.gov/cgs/rghm/rgm/250k_index/250k_index.htm
http://www.consrv.ca.gov/cgs/rghm/rgm/index.htm
http://www.consrv.ca.gov/cgs/information/geologic_mapping/
http://www.consrv.ca.gov/cgs/

4. Visit the map library of the university or
college nearest what you are studying. They will
a collection of local mapping and, typically, have
a collection of digital mapping and other GIS
cartographic data that a peson obtain copies of.

Some of the important stuff to look for are:

(1.) DEMs (Digital Elevation Model) from
 1:24,000 maps and other topographic maps.

http://130.166.124.2/ca_dems.htm

(2.) DEMs (Digital Elevation Model) from
LIDAR (Light Dectection And Ranging)
flights. ****If available, this data are as good
as gold**** for any sort of geomorphologic
research. Stuff that doesn't even show up on
satellite images will show up on the DEMS.

(3.) DOQQs (Digital Orthophoto Quarter Quads)
These show the land surface with as much as
1 to 10 meter resolution. Get the color DOQQs,
if available.

(4.) DRGs of 1:24,000 maps that are
georeferenced.

(5.) US Agricultural Stabilization and Conservation
Service aerial photography. Many libraries have it
on hand. This is good stuff because it is typical
at a scale of 1:2,000. The indexes and individual
aerial photos can be ordered from

US Agricultural Stabilization
   and Conservation Service
2505 Parley's Way
Salt Lake City, UT 84109.

It is black and white, but still useful.

(6.) USGS aerial photgraphy, e.g., National Aerial
Photography Program (NAPP) and other types of
aerial imagery. Go see:

http://edc.usgs.gov/products/aerial/napp.html

(7.) Don't forget paper 7.5 minute topographic
maps. Even though they are old, the now
discontinued 15 minute maps are very useful
getting an excellent overview of and feel for an
area's landscape.

5. then, look through the EROS Data Center at:
http://edc.usgs.gov/ for their satellite, GIS,
and other cartographic data that can be found
in the area of interest.

Some California web pages

http://geogdata.csun.edu/
http://gis.ca.gov/index.epl
http://gis.ca.gov/DRG.epl
http://casil.ucdavis.edu/casil/usgs.gov/
http://www.lib.berkeley.edu/EART/digital/dem/dem.html

A good map of whatever being looked at is
essential, whether it be topographic map or
aerial photography. If a person don't where
they are, they are nowhere.

Yours,

Paul
Baton Rouge, LA



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Received on Mon 05 May 2003 09:53:16 PM PDT