Santa Rita Experimental Range

Repeat Photography




This database includes repeat photography images for 117 locations on the SRER, accompanying text written by the photographers that describes the vegetation and other attributes of the scene, and UTM coordinates of the photo station locations. The collection can be accessed at http://ag.arizona.edu/SRER/. Access to photographs and text for a photo station location can be made through the photo station number or from a hyper-linked map of photo station locations on the SRER. Mitchel McClaran (lead author) recorded the UTM coordinates with a Global Positioning receiver between 1998 and 2000 when repeat photography was performed. The coordinates are projected in the NAD83 datum using the GRS1980 spheroid. The images can be downloaded as tagged image format files (*.tif) or copied as images in the graphical interchange file format (*.gif).

The images are accompanied by a Photo Archive number that identifies the location, direction, year, and month of the photograph. For example, the Photo Archive number 45.1.1948.06 identifies the image as being made at photo station 45 (or PS 45), looking in the direction that is closest to north and on the east side of north, in the year 1948, and the sixth month or June. The direction code ranges from 1 to 7: about half of the locations have photographs taken in only one direction, and about 40 percent have two directions. One location (PS 42) has seven locations that are arranged to provide a 360 degree view. When more than one direction is included for a photo station, the value of 1 was assigned to the direction closest to north on the east side of north, and subsequent values increased in a clockwise direction.

The earliest photographs were taken by Griffiths (1904) between 1902 and 1905 at 16 different locations (PS 219, 220, 221, 222, 224, 228, 229, 230, 231, 233, 234, 251, 332, 333, 334, and 335). The average interval between photographs is approximately 15-20 years, but some locations have repeat photographs made twice a year for a period of up to eight years.



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Last updated: 26 October 2001
Mitchel McClaran: mcclaran@u.arizona.edu