--- Begin Forwarded Message ---
Date: Wed, 10 Oct 2001 16:24:54 -0400
From: HelenJane Armstrong <[log in to unmask]>
Subject: RE: aerial photos: advice needed <fwd>
Sender: HelenJane Armstrong <[log in to unmask]>
Hello Mark
Welcome to the wonderful world of aerial photography.
At the University of Florida, we have over 300,000 aerial photographs.
Approximately one third of the total patron use of the Map & Imagery Library
involves aerial photographs. The clientele includes undergraduate students
to scholarly researchers, private consultants, state agencies and private
citizens. In the 1970's, I arranged with the State Office of the then US
Dept. of Agriculture ASCS to serve as an archives for all of the older
contact prints for each of Florida's 67 counties. In the past 25 years, we
have added numerous photos by gift, transfer and purchase. Currently we
have archival flights from 1937 through 1980 plus the latest flights for our
home county and some often studied areas.
Given this background, the following are my observations based on your
questions:
.We have acquired both stereo and physical landscape coverage from the
County Soil Conservation Offices. Over 75% of our patrons are satisfied
with physical landscape coverage even when the stereo pairs are an option.
We have purchased physical landscape coverage for every county that has not
been designated as a priority site. For our local county we purchase stereo
pairs and the biggest enlargements available for our city. We also acquire
stereo pairs and enlargements for St. Augustine, a Natural Preserve, and a
Marine Studies Area. The enlargements are expensive but extensively used.
In addition we are buying the ColorInfra Red aerial photographs for these
areas but not in stereo.
I do not think you would be irresponsible to purchase landscape coverage if
the primary use of your clientele is to locate sites, do temporal
comparisons, etc. However, if the photos are to be used for precise
measurements and/or photogrametric interpretation, this could change the
situation. As you know the aerial photograph becomes distorted the further
you move away from the center point. This creates some problems for GIS
layers when the area one is studying is at the edge of the two photos in
physical coverage but the center in stereo coverage. You should survey your
user group first. If you don't have engineers and other specialists
requesting stereo pairs than you probally are safe in ordering the physical
landscape coverage.
The enlargements and CIR photos are expensive but have been well worth it.
Anyone studying our local city, Gainesville, inevitably requests the
enlargements back to 1938. The CIR photos for the 1999 flight are used
extensively by everyone despite huge differences in expertise.
Finally, why don't you offer to be the archives for your local Ag extension
of NRS office? If they have a space problem and want the photos organized,
you might get lucky like we did. Originally we provided a computer listing
of every photograph in our collection. We still maintain the list for
inventory purposes but now the agencies just refer people to us. This has
led to gifts of aerial photos from consulting firms and museums.
These are just my first reactions to your questions. If you would like to
discuss any of this further, please give me a call. Also, I have been
ordering a lot of aerials and photos from the USDA and National Archives and
would be willing to share information with you.
Good Luck with your project
Helen
> > > HelenJane Armstrong, PhD
> > > Head, Map & Imagery Library
> > > George A. Smathers Library
> > > University of Florida
> > > P.O.Box 117011
> > > Gainesville, FL 32611-7011
> > > EMAIL: hjarms@mail
Phone: 352-392-2828
-----Original Message-----
From: Johnnie Sutherland [mailto:[log in to unmask]]
Sent: Wednesday, October 10, 2001 12:56 PM
To: [log in to unmask]
Subject: aerial photos: advice needed <fwd>
--- Begin Forwarded Message ---
Date: Tue, 9 Oct 2001 19:52:18 -0400 (Eastern Daylight Time)
From: Mark Thomas <[log in to unmask]>
Subject: aerial photos: advice needed
Sender: Mark Thomas <[log in to unmask]>
I need advice on purchasing some historic aerial photos of
our local county from USDA in Salt Lake City. I have the
indexes of the county for the flyovers that I'm interested in.
When you order from Salt Lake, you give them the sequence of
exposures (from index) and tell them whether you want
stereoscopic coverage (consecutive exposures), or physical
coverage (alternate exposures). Since there are only about half
the prints, physical coverage is about half the cost, but you
don't have the overlap you need to view stereoscopically.
QUESTION: How likely will it be that patrons will need to study
the photos in stereo? Is it worth the extra cost to have all
images available? Is it irresponsible to be cheap and get just
enough shots for "physical coverage," but preclude the future
option of looking at them in stereo? It depends on the scale of
the particular coverage, but we might be talking about $500
versus $1000 for a particular year.
Our use would be low. We get occasional users interested in
change over time in the local landscape. Maybe some community
users; maybe some researchers and students in the School of the
Environment or in the occasional History of Public Policy
seminar that deals with local issues.
I'm asking because we've never actively collected aerial photos
so I need advice from places that have more experience with
them. We currently have only a 1972 USDA (NRCS) flyover of
Durham Co, NC, and the photomosaic index for that and for a 1966
FSA set. I was interested in purchasing some more 1950s and
1960s coverages of the county. I'm worried about the older
stuff being transferred to NARA (1937, 40, and 51 already have),
whereupon it becomes several times more expensive (the
reproduction of NARA images is privatized). Our local ag
extension and similar offices have some of these old images
stuffed in old filing cabinets, all out of order, like garbage.
Not complete sets that I could tell from looking through them
for an hour or so.
thanks,
Mark
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Mark Thomas / [log in to unmask] / 919-660-5853, fax:919-684-2855
Map and GIS Librarian / Economics Bibliographer
Public Documents and Maps Department
025 Perkins Library / Duke University, Durham, NC 27708-0177
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