"Aerial photography." . . "National Research Council (United States). Highway Research Board." . . "Mapping." . . "Engineering soil survey mapping : presented at the Thirtieth Annual Meeting, 1951"@en . . . . "Engineering ; Soil survey mapping : presented at the Thirtieth Annual Meeting 1951" . "Contains a group of related papers on the use of aerial photographs to abtain terrain information, such as, type of soils, parent material and drainage from the study of airphoto soil and rock patterns. The status of current geologic and agricultural soil mapping are indicated, and revised lists of geologists and soil scientists are given."@en . . . . . . . . . . . . "Maps"@en . "Engineering soil survey mapping presented at the Thirtieth Annual Meeting, 1951"@en . . . . "Geological surveying." . . . .