Identification and measurement of shrub type vegetation of large-scale aerial photographs

Abstract

Important range-shrub species were identified at acceptable levels of accuracy on large-scale (1:600 to 1:1,500) 70 mm color and color infrared aerial photographs (positive transparencies). Identification of individual shrubs was significantly higher, however, on color infrared. Eight of 11 species were identified correctly more than 80 percent of the time on color infrared and two species were correctly identified 100 percent of the time. Six species were identified more than 80 percent correctly on color photographs but none were identified 100 percent correctly. Photoscales smaller than 1:2,400 had limited.value except for mature individuals of relatively tall species, and then only if crown margins did not overlap and sharp contrast was evident between the species and background. Larger scale photos (1:800 or less) were required for low-growing species in dense. stands. The crown cover for individual species as estimated from the aerial photos either with a measuring magnifier or a projected-scale micrometer. Photo measurements were significantly correlated with ground measurements. These crown cover measurements provide techniques for earth-resource analyses when used in conjunction with space and high-altitude remotely procured photos.

Citation

Driscoll, Richard S. 1970. Identification and measurement of shrub type vegetation of large-scale aerial photographs. In: Third annual earth resources program review, Vol II: Agriculture, forestry, and sensor studies; ASA Manned Spacecraft Center; Houston, TX; December 1-3, 1970. Washington, DC: National Aeronautics and Space Administration. p. 32: 1-15.