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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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