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| Maps Section | contact: Publications(publications@mgs.md.gov) |
ORTHOPHOTO QUADRANGLES
ORTHOPHOTO QUARTER-QUADRANGLES (3.75-MINUTE SERIES).
These are ortho-corrected (parallax-free) photographic images (either digital or analog reproduction) of "quarter quads" —i.e., one-fourth of a standard 7.5-minute quadrangle. Scale 1:12,000 (1 inch equals 1,000 feet); size approximately 24 inches by 31 inches. Prepared by PhotoScience, Inc., Rockville, MD, for the Maryland Department of Natural Resources - Water Resources Administration. Incomplete coverage of the state. Contact the MGS Publications Office at (410) 554-5505 for information concerning coverage for a particular area of interest. Dates vary; generally 1989-1993. Blueline copies only..................$4.00
DIGITAL ORTHOPHOTO QUADRANGLES.
Series of 102 digital orthophoto quadrangles and 8 digital orthophoto quarter-quadrangles covering the Chesapeake Bay area of Maryland, including the tidal reaches of the major bay tributaries. The source documents—black and white Kodak paper prints— were produced by the U.S. Geological Survey from 1988-1989 National Aerial Photography Program (NAPP) photography and comply with National Map Accuracy Standards at 1:24,000. Rasters were produced by scanning the paper prints at 1000 dots/inch (dpi) and down-sampling to 250 dpi (ground pixel size = 8×8 ft.). Color depth is 8 bits (256 gray levels). Map collars were excluded from the scan; place names, neat lines and Universal Transverse Mercator (UTM) grid lines are an inextricable part of the image. Files are approximately 30 megabytes in size and are available on CD-ROM, erasable optical disk, or, for small orders ( 5 quads), via the Internet. Native format is MicroImages .RVC; .TIFF format is also available. Detailed documentation, compliant with federal metadata standards, is transferred in ASCII format with the files. Purchasers are required to sign a licensing agreement.
| Contact Lamere Hennessee at lhennessee@mgs.md.gov or (410) 554-5519. Do not direct inquiries pertaining to digital products to the MGS publications office. |
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| Quads (excluding media) | Media |
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