These files contain topographic data obtained by airborne scanning laser altimetry, or LIDAR, surveying. Further information may be found at www.pugetsoundlidar.org The data are in State-plane projection (Washington North zone, ARC zone 5601, FIPS zone 4601). The vertical datum is NAVD88, horizontal datum is NAD83. Raster cells (grid cells, image pixels) are 6 ft square. Elevations are recorded in floating-point feet. The ARC-INFO projection information for these data is Projection STATEPLANE Zone 5601 Datum NAD83 Zunits FEET Units FEET Spheroid GRS1980 Xshift 0.0000000000 Yshift 0.0000000000 Parameters Naming Conventions ------------------ .e00.gz gzipped ARC .e00 file of raster elevations .j.zip zipped JPEG and world file, NE-illum. hillshade .jpg JPEG (web-viewable) of NE-illuminated hillshade Disclaimer ---------- We have taken considerable care to ensure that these topographic survey data and derived images are as accurate as possible. We believe most of these data are adequate for determination of flood hazards, for geologic mapping, for hydrologic modelling, for determination of slope angles, for modelling of radio-wave transmission, and similar uses with a level of detail appropriate to a horizontal scale of 1:12,000 (1 inch = 1,000 feet) or smaller and vertical accuracy on the order of a foot. Locally, the data are of considerably poorer quality. You should carefully determine the place-to-place accuracy and fitness of these data for your particular purposes. For many purposes a site- and use-specific field survey will be necessary. Enjoy! The Puget Sound LIDAR Consortium