BASE MAP The base map for the digital compilation is a shaded relief map from Digital Elevation Model (DEM) created with the Light Detection and Ranging (LiDAR) data at 4x vertical exaggeration, a sun azimuth at 45 degrees, and sun vertical angle at 45 degrees. The LiDAR data was acquired from the Puget Sound LiDAR Consortium and King County Endangered Species Act/Sensitive Areas Ordinance, LiDAR Digital Ground Model (DGM), 2001-2003. Horizontal accuracy is ~1.8 meters; vertical accuracy is ~0.3 meters.Street data was extracted from City of Seattle, WA, 1:1200-scale proprietary street data, 2001. Horizontal accuracy is ~1.5 meters.
SPATIAL RESOLUTION Uses of this digital geologic map should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. The fact that this database was edited at a scale of 1:12,000 means that higher resolution information is not present in the dataset. Plotting at scales larger than 1:12,000 will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Similarly, where this database is used in combination with other data of higher resolution, the resolution of the combined output will be limited by the lower resolution of these data.