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Catalog Definitions and Helpful Information |
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| As we gather feedback on the current catalog, we will post Frequently Asked Questions here. In the meantime we've provided information on the aerial indexes as well as field definitions for the catalog records. |
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Historical aerial photography index maps and photomosaic indices For collections housed at the Robinson Map Library at the University of Wisconsin-Madison, the aerial photo indices are available online to aid in the selection of the proper flight-line and exposure number(s) needed to cover the area of interest. These indices show flight-line and exposure numbers on either base map or photo-mosaic, but serve the same purpose. Exposures that appear circled are those that the Map Library actually holds. These can be accessed and electronically scanned to a CD-ROM within the library. |
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Data Dictionary - WI Catalog of Aerial Photography field definitions Though we have made an extensive effort to ensure complete and accurate information, the quality of the data presented in this catalog is largely dependent on what was reported. If you find any discrepancies or are aware of missing photo information, please contact the SCO. |
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Year This lists the year in which the photography was acquired. Some projects, such as the National High Altitude Program (NHAP), were completed over several years. In these cases a range of years is given. It also lists the Season (or Month) when the photograph was acquired. This date is important for determining whether the photography is "leaf-on" (deciduous vegetation with leaves) or "leaf-off". |
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Format This entry lists the type of film. Abbreviations are: B&W = Black-and-white (panchromatic) B&W IR = Black-and-white infrared COLOR = Natural color COLOR IR = Color infrared (false color) Infrared film is typically used to view differences between types of vegetation and to clearly see the distinction between water and land. |
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Scale Both ratio (1 : n) and the equivalent inch scale (1" = n') values are provided. This is the scale of the original photography as taken in the aircraft. Most aerial photography is taken with a large format camera using 9"x9" film. Since the size of aerial film is the same, the scale and thus the detail visible on a photo depends on flying height above the ground. As an example, a photo at 1:20,000-scale (1"=1667') covers one quarter the area and shows objects at twice the size as a 1:40,000-scale (1"=3,333') photo. This results because the 1:20,000-scale photo was flown at half the altitude of the 1:40,000-scale photo. When enlargements of the photos are produced, scale increases. |
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Extent Provides a brief description of the approximate area covered by the photography. If necessary, this is followed by a more detailed description of the coverage. |
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Other Information The above reference items for each aerial photography project are intended to provide enough information for the user to identify photo resources that meet specific needs. The information describes the entire project, but is not intended to be sufficiently detailed for identifying specific images by roll and frame number. Also, we have not included information on prices since frequent changes would make this information obsolete. Users should select the desired project(s) and then use the contact address to obtain more detailed information. |
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Who to Contact The contact addresses reference a wide variety of organizations that collectively account for a large amount of aerial photography. Readers with questions about a project are encouraged to contact the appropriate address. The catalog's address listing does not represent all the potential sources of photography in the state. If no address for the area of interest is listed, we recommend that you contact an organization responsible for administering the area, such as a county government office, a city engineer, or a park supervisor. |