This part of USGS Data Series 935 (Cochrane, 2014) presents bathymetry and topography data for the Offshore of Seattle, California, map area, a part of the Southern Salish Sea Habitat Map Series. The data for this map area are a combination of topography extracted from a pre-existing Digital Elevation Model (DEM) merged with bathymetry data that were collected by the National Oceanic and Atmospheric Administration (NOAA) using multibeam sonar systems. The merged data are available for download in a single zip file (BathyTopo_OffshoreSeattle.zip).

1ft contours along the City of Seattle shoreline derived from Lidar captured in 2021. Contour lines display at 1ft, 5ft and 20ft intervals dependent on scale.Development Detail:This vector tile service includes topographic contour lines representing elevation at 1-foot intervals within the City of Seattle shoreline area.The contours were derived from a bare earth - digital elevation model (DEM) with a pixel resolution of 1.5 feet. The lidar data that created the DEM were collected by NV5 Geospatial over the spring and summer months of 2021 and provided to the city by King County in 2022.The DEM used to generate the contours was filtered using the Focal Statistics tool in ArcGIS, which served to limit some abrupt changes in cell values. A 3x3 rectangular neighborhood analysis was applied and a mean value was calculated per raster cell.After generating the contours from the generalized raster, all lines less than 25 feet in length were omitted from the final output.Please note: The 1-foot contours are intended to be used for general reference and cartographic purposes only and should not be used for analysis purposes.

City of Seattle 2 ft contours derived from Lidar captured in 2021. Contour lines display at 2ft, 10ft and 50ft intervals dependent on scale. Lines have been smoothed and generalized for display and performance.

Development Detail:

This vector tile service includes topographic contour lines representing elevation at 2-foot intervals within the city of Seattle.

The contours were derived from a bare earth - digital elevation model (DEM) with a pixel resolution of 1.5 feet. The lidar data that created the DEM were collected by NV5 Geospatial over the spring and summer months of 2021 and provided to the city by King County in 2022.

The DEM used to generate the contours was filtered using the Focal Statistics tool in ArcGIS, which served to limit some abrupt changes in cell values. A 3x3 rectangular neighborhood analysis was applied and a mean value was calculated per raster cell.

After running the Focal Statistics tool, 2-foot contours were generated from the filtered DEM. To reduce file size and improve performance, the contours were generalized further using the Smooth Line tool in ArcGIS. A smoothing algorithm type of Polynomial Approximation with Exponential Kernel (PAEK) and a smoothing tolerance of 20 feet was selected in the Smooth Line tool parameter options.

Finally, after executing both generalization tools (Focal Statistics and Smooth Line), all lines less than 25 feet in length were omitted from the final output.

Please note: The 2-foot contours are intended to be used for general reference and cartographic purposes only and should not be used for analysis purposes.

This digital elevation model (DEM) is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer. The DEMs created for this project were developed using the NOAA National Weather Service's Weather Forecast Office (WFO) boundaries. Because the WFO boundaries can cover large areas,...

Landforms in Seattle, Washington, that were created primarily by landsliding were mapped using LIDAR-derived imagery. These landforms include landslides (primarily landslide complexes), headscarps, and denuded slopes. Over 93 percent of about 1,300 reported historical landslides are located within the LIDAR-mapped landform boundaries. The spatial densities of reported historical landslides within the LIDAR-mapped landforms provide the relative susceptibilities of the landforms to past landslide activity. Because the landforms were primarily created by prehistoric landslides, the spatial densities also provide reasonable estimates of future landslide susceptibility. The mapped landforms and susceptibilities provide useful tools for landslide hazard reduction in Seattle.

[Summary provided by the USGS.]

The polygons are intended for use by the City of Seattle as planning-level tool for a preliminary understanding of the drainage patterns in particular areas of the City. The layer is not complete and does not reflect any City determination about how specific locations should be characterized. Drainage Basins areas were delineated using topography, roads and utility infrastructure based on current GIS data, 200-foot scale maps, side sewer cards and engineering design documents. Data source is DWW.drainage_basin_plgn_pv. Labels are based on the attribute NAME.

TerraPoint surveyed and created this data for the Puget Sound LiDAR Consortium under contract. The area surveyed is approximately 1,146 square miles and covers part of Kitsap Peninsula, the Seattle area north to the King-Snohomish county border and east to Snoqualmie. The data is broken down into USGS quarter quads and then into 25 tiles within each quarter quad.

All data was collected during...

This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found

Displays areas with 40% steep slope or greater in the City of Seattle.A polygon feature class showing areas with an incline of 40% or more (10 feet of vertical rise over a horizontal distance of 25 feet or less) with a height of at least 10 feet. This layer was produced using a combination of 2001 LIDAR contours (Puget Sound LIDAR Consortium) and the 1993 topographic contours from aerial photos. The Steep Slope layer was most recently updated under SDCI Director's Rule 12-2019. The steep slope area map is called “advisory” because the mapping is used by the Seattle Department of Construction and Inspections for initial information and screening. Whether or not a site is eventually treated as an environmentally critical area is based on the actual topography of the ground surface. For more information about the definition of steep slope erosion hazard areas, see Seattle Municipal Code section 25.09.012, Environmentally Critical Areas (ECA) definitions. Because of the size of this dataset, we do not recommend trying to download it. Please use as a service. If you need a particular area extracted, please use this form to make a request:<a href='https://forms.office.com/Pages/ResponsePage.aspx?id=RR7meOtrCUCPmTWdi1T0G9zIhm_E9thFiIFY5ws9oKtUQUlNU0hTQ0pGQlhOUDNSOExZQlhXM01INi4u' style='color:rgb(0, 97, 155); text-decoration-line:none; font-family:inherit;' target='_blank' rel='nofollow ugc

Glacier Peak is a 3,214 m (10,544 ft.) stratovolcano composed mainly of dacite. The volcano is located in the Glacier Peak Wilderness Area, in the Mt. Baker-Snoqualmie National Forest, about 100 km (65 mi) northeast of Seattle and 110 km (70 mi) south of the International Boundary with Canada. Since the continental ice sheets receded from the region approximately 15,000 years ago, Glacier Peak has erupted repeatedly during at least six episodes. Two of these eruptions were among the largest in the Cascades during this time period. This DEM (digital elevation model) of Glacier Peak is the product of high-precision airborne lidar (Light Detection and Ranging) surveys performed during August-November, 2014 and June, 2015 by Quantum Spatial under contract with the USGS. This digital map, totaling approximately 475 square miles, represents the ground surface beneath forest cover and contributes to natural hazard monitoring efforts, the study of regional geology, volcanic landforms, and landscape modification during and after future volcanic eruptions, both at Glacier Peak or elsewhere globally. This release is comprised of a DEM dataset accompanied by a hillshade raster, each divided into 18 tiles. Each tile’s bounding rectangle is identical to the extent of the USGS 7.5 minute topographic quadrangles covering the same area. The names of the DEM tiles are eleven characters long (e.g., dem_xxxxxx). The prefix, "dem", indicates the file is a DEM and the last seven characters correspond to the map reference code of the quadrangle defining the tile's spatial extent. Hillshade tile names are denoted by the prefix "hs", but are otherwise identical to the DEM they are derived from.

The shoreline essentially follows the 8 foot contour line, except where the ortho offered further clarification. That 8 foot contour line matches closest to what NAVD88 shows as "mean high water" (see official definition below) at 7.97 feet. MEAN HIGH WATER (MHW): "A tidal datum. The average of all the high water heights observed over the National Tidal Datum Epoch. For stations with shorter series, simultaneous observational comparisons are made with a control tide station in order to derive the equivalent datum of the National Tidal Datum Epoch." Source "The MHW line along the tidal shoreline is represented by the contour line that is 8.0' above the NAVD 88. The MHW elevation is not necessarily an equipotential (level) surface, but the variation from a level surface is not significant for this project. The determination of MHW is based on 18 yrs of tidal data and represents the latest official National Tidal Epoch of 1960-1978. The Seattle Tide Station (Sta No 944-7130) is located at the downtown ferry terminal." Source: From paper by Nick Bodnar 10/18/1993 Some other definitions regarding these shorelines (from Nick Bodnar, 10/18/1993): LAKES UNION AND WASHINGTON SHORELINE (18.6' above NAVD 88) The approximation of "ordinary high water"; the level of Lk Washington varies from 17.0'-18.6' during the year; the max lake elevation is 18.8' as controlled by Corps of Engineers (COE) at Hiram Chittenden Locks. The NAVD 88 lake elevations have been converted from the U.S. Engineers Datum. This zero of NAVD 88 is 3.25' above the Locks Datum at the common bench mark P-7. The shoreline contour of 18.8' above NAVD 88 should be used from the Locks, upstream through Lk Union and Lk Washington. The COE has performed various studies that show the level of Lk Wash to approximate an equipotential surface that can be represented by a single contour elevation for mapping purposes. OTHER LAKES The shoreline around Green Lake and all other lakes are delimited by the water/land interface as seen on the aerial photography.

Displays data from CARTO.SHORE_LNUpdated as needed.

Displays areas with liquefaction zones.A polygon feature class that shows liquefaction zones. Used to implement and regulate the City of Seattle's Environmentally Critical Areas (ECA) policies. This layer was created in 1995 using data obtained from the USGS. Some edits were made to the edges to better coincide with the City's two foot contour data.Areas of the City subject to ground shaking from seismic hazards that are addressed by Title 22.The Seattle Fault zone as delineated in Troost et al., 2005, The geologic map of Seattle, a progress report, U.S. Geological Survey, Open-file report 2005-1252 , or as the Director determines is more accurately mapped by the U.S. Geological Survey, as set out in a Director's Rule.For more information about the definition of liquefaction zones, see Seattle Municipal Code section 25.09.012, Environmentally Critical Areas (ECA) definitions. Updated as needed.

Displays areas of landslide events based on a Seattle Landslide Study completed by Shannon and Wilson.A polygon feature class showing landslide event inventory. Used to implement and regulate the City of Seattle's Environmentally Critical Areas (ECA) policies. This layer includes a more comprehensive collection of slide events maintained by Shannon and Wilson via the Seattle Landslide Study which included slide data through June 1999.The Known Slide layer was most recently updated under SDCI Director's Rule 12-2019.For more information about the definition of known slide areas, see Seattle Municipal Code section 25.09.012, Environmentally Critical Areas (ECA) definitions.Updated as needed.