Classified polygons covering the Columbia River estuary were derived from the U.S. Coast & Geodetic Survey historic topographic survey maps (T-sheets) from 1868 to 1901. Hydrographic sheets (H-sheets) provided bathymetric depth values which were converted into a DEM. These products are provided in an ArcGIS personal geodatabase.
Download T-sheets (classified landcover)
Download T-sheets (georeferenced images)