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Overview, Oregon -- see Loy et al. (2001), Atlas of Oregon : 18-19. [Not available digitally].
Topographic maps ("T-sheets") of the U.S. Coast Survey (later called U.S. Coast and Geodetic Survey, and more recently the National Geodetic Survey) have been integrated whenever possible with GLO data because of the data-rich detail they impart to map products. They were based on meticulous field mapping conducted between 1852 and 1889. Cartography of the Coast Survey maps was superior to that of the GLO township plat maps, and when georeferenced, is substituted for linework shown in the plat maps.
The Coast Suvey maps provide highly accurate delineations of small-patch vegetation and stream alignments at a level of detail not possible from GLO data, while the GLO data provide information on vegetation, streams, and cultural features that are not available from Coast Survey data. When combined, the two sources of information provide high-quality cartography on the composition and extent of various vegetation types at the time of survey.