The Origin, Distribution, and Airphoto Identification of United States Soils

Aerial photographs in geologic interpretation and mapping

“…From the standpoint of engineering significance a granular material, for example, which exhibits certain diagnostic photographic characteristics such as coarse-textured drainage, will generally react favorably to drainage, compactability, and other engineering tests, regardless of whether it is a residual granular material that has resulted primarily from weathering in place or whether it is a transported gravel derived from different rock types. However, Jenkins, Belcher, Greeg, and Woods (1946) pointed out exceptions to the general thought that photographic characteristics common to granular materials always signify suitable granular materials for engineering purposes. For example, the soil profile of well-drained limestone has a granular texture due to aggregation of clay particles into lumps.…”

“…(See Belcher, 1945Jenkins, Belcher, Greeg, and Woods, 1946;Frost, 1946;Frost and Woods, 1948;Hittle, 1949;andParvis, 1947, 1950. ) In areas where resistance to erosion may be more or less uniform, as in many surficial deposits or in bedrock without pronounced structure, the drainage pattern is commonly dendritic or modified dendritic (see figs.…”

“…Much of the literature concerns reconnaissance studies of soils in general and granular materials in particular; granular materials are essential for building sites and highway and airport development (Jenkins, Belcher, Greeg, and Woods, 1946;and Purdue University, 1953). Special attention also has been given to photointerpretation of permafrost conditions in northern latitudes.…”

“…The soil pattern consists of several elements of which the most important ones for nonpermafrost areas are considered to be landform, drainage, erosion, relative photographic tone, and color; vegetation cover and land use may also be significant (Belcher, 1944(Belcher, , 1945(Belcher, , 1948Jenkins, Belcher, Greeg, and Woods, 1946;Frost, 1946;Mollard, 1947;Hittle, 1949;and Purdue University, 1953). Schultz and Cleaves (1955, p. 371) considered that "interpretation of soils by means of aerial photographs rests largely on the interrelationships of soils and geomorphic features"; consequently landform is considered by some to be the most important element in photointerpretation of soils.…”

The Use of Aerial Photography in Mapping Soil Sites

“…), are also helpful in the integrated soil site. In the main, however, techniques for mapping soils, (Bushnell, 1927;Baldwin et al, 1947), geologic materials, (Thwaites, 1946, Jenkins, Belcher et al, 1946, topography, (Lobeck and Tellington, 1944;Smith, 1944), place the main emphasis on the criterion of landform and are, therefore, largely applicable to non-forested areas. Even there, as Smith (1944) points out, it is only relative slope and relative relief that can be observed unless special instrumental equipment is used and ground control established.…”