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PHOENIX — An online archive of historical aerial photographic images of Maricopa County was enhanced in November to include a collection of photographs from a 1930 archaeological survey of the Phoenix area. The public may view the images through an interactive map application on the Flood Control District of Maricopa County’s Web site.
The District’s Geographic Information Systems (GIS) department manages an archive of more than 71,000 black-and-white and color aerial photographs shot over parts of the county in various years from 1930 through 2007 (updated 2008 images will be available soon). The images may be viewed at www.fcd.maricopa.gov, via the “Maps” link on the home page.
Visitors to the District’s Web site have unrestricted viewing access of the images. The photos may be viewed for free using a map application which groups the images by year. The images may also be purchased for commercial and personal use. For more information, please call the District at 602-506-1501.
The 1930 aerial photographs were shot as part of a comprehensive archaeological expedition commissioned by the Smithsonian Institution and Department of War to document Hohokam canals and other ruin sites. Both vertical (straight down) and oblique (at an angle) photos were shot over central Phoenix east through Tempe and Mesa.
The oblique photographs provide an almost 3-D effect. The pristine Salt River corridor and patchwork of ranches and farm fields in the Great Depression-era photos are a sharp contrast to the freeways, shopping malls and sprawling subdivisions which fill the images from more recent years. Eagle-eyed viewers can spot the old Hayden flour mill in Tempe and evidence of ancient Hohokam canals.
The photos were tucked away in storage at the Smithsonian for 75 years until displayed to the public in 2006 at the Pueblo Grande Museum in Phoenix. The District’s GIS department became interested in the photos following the museum exhibit.
“We thought it would be a shame to let these high-quality images gather dust in a museum when they could be used for modern-day purposes,” said Marta Dent, District GIS manager.
The department secured acquisition, copy and distribution rights from the Smithsonian for digital files of the approximately 500 images. GIS staff cataloged and “geo-referenced” the photographs, determining each image’s particular coordinates on the ground to accurately place the image into the Web site map application.
When the District initially received the oblique photos, many did not have identified locations. A request was posted on the Web site asking for help from the public in identifying the locations of the images. Response to the query was so good that GIS staff expect to have all the oblique images identified by the end of 2008.
The District’s in-house GIS staff provides cartographic and database support critical to District services such as floodplain management, planning, identification of historical drainage patterns and public meetings. And while the aerial photographs are primarily for the District’s internal use, the archives also provide a terrific resource for the public, considering the large volume of images and the ease of viewing for anyone with Internet access.
The District is constantly pursuing opportunities to fill gaps in its aerial photograph archive. Images for the years 1957, 1976 and 1986 are pending projects.
The historical aerial photographs complement the District’s 100-year FEMA floodplain maps and countywide elevation contour maps, also found on the agency’s Web site.
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