--- 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 --- End Forwarded Message ---