Population and Building Density for Clackamas, Multnomah, and Washington Counties, Oregon

Oregon Department of Geology and Mineral Industries 2018 Population and Building Density for Clackamas, Multnomah, and Washington Counties, Oregon vector digital data Oregon Department of Geology and Mineral Industries Open-File Report Open-File Report O-18-02 Portland, Oregon, USA Oregon Department of Geology and Mineral Industries http://www.oregongeology.org Oregon Department of Geology and Mineral Industries 2018 Earthquake regional impact analysis for Clackamas, Multnomah, and Washington Counties, Oregon file geodatabase Oregon Department of Geology and Mineral Industries Open-File Report Open-File Report O-18-02 Portland, Oregon, USA Oregon Department of Geology and Mineral Industries http://www.oregongeology.org/ Population density map, showing number of permanent residents, residential buildings, and total number of buildings per 20-acre hexagonal cell. 1) Overlay purposes: the layer can be used to quantify number of buildings and people relative to a natural hazard. 2) Visualization of the 3-county population density 2018 Complete None planned -123.394279 -121.697823 45.807359 44.870218 ISO 19115 Topic Category geoscientificinformation society Oregon Geospatial Enterprise Office Metadata Keyword Thesaurus building Residential Oregon Geospatial Enterprise Office Metadata Keyword Thesaurus Clackamas Multnomah Washington Oregon Geospatial Enterprise Office Metadata Keyword Thesaurus Building Space Oregon Geospatial Enterprise Office Metadata Keyword Thesaurus None REPORT DATA: This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary data and information sources to ascertain the usability of the information. This publication cannot substitute for site-specific investigations by qualified practitioners. Site-specific data may give results that differ from the results shown in the publication. See the accompanying text report for more details on the limitations of the methods and data used to prepare this publication. Oregon Department of Geology and Mineral Industries mailing and physical address

800 NE Oregon Street Suite 965

Portland Oregon 97232 USA 1 971 673 1555 1 971 673 1562 dogami-info@oregon.gov When contacting DOGAMI about this data set, please reference the data set title or other identifying information in your correspondence. DOGAMI publications can be downloaded from http://www.oregongeology.org John Bauer Oregon Department of Geology and Mineral Industries Geohazards Analyst jpeg image (.jpg) This work was funded on behalf of Regional Disaster Preparedness Organization with an Urban Area Security Initiative grant for the Portland Metropolitan Region. Unclassified Some buildings may span a hexagonal boundary. They are associated with where the building centroid resides. Hexagonal boundaries are arbitrary, and do not recognize any streets, jurisdictions, or hydrographic features. Total building count is the same as represented in the Jurisdictions and NeighborhoodUnits feature classes. Permanent Resident quantities assume that residential buildings (excepting the hotel/motel type) are properly identified in the building database. Some may be misidentified as residential, and some fractional amount of people were placed in the building. Permanent Residents attribute is a fractional number due to the prorating of people across all residential structures in a Census Block Group , on a per-building-square-footage basis. While believed to be good, it may over- or under-estimate number of permanent residents in a given hexagonal cell. Second homes, designated as Residential in the database, will be populated with some permanent resident amount, given our methods, though in practice the building is only occasionally occupied. Population numbers should not be considered authoritative. They are an approximation of the permanent resident population distribution. Hexagonal cells with no buildings were removed from dataset. Remaining cells do not overlap. All cells populated with building count and an estimate of the number of permanent residents. All areas in the three counties fully represented, as the building footprint database was considered complete. Note that the building footprint database may not contain all buildings, especially in remote areas with heavy canopy. Hexagonal cells in the US Highway 26 Zigzag/Rhododendron corridor will note the presence of a building, though none exists in the building footprint feature class. In these cases, a tax lot centroid where buildings were known to exist was used as a basis for establishing presence of a building. Building footprints were generally digitized at 1:1000 scales, and form the basis for this aggregation dataset. Building footprint centroids were associated with the hexagonal cell. Not applicable Esri 20130703 Create Hexagon Tesselation model Esri https://www.arcgis.com/home/item.html?id=03388990d3274160afe240ac54763e57 20130703 A 20-acre hexagonal grid was created using the "Create Hexagon Tesselation" geoprocessing package (Esri, 2013) that covered the 3-county area. Building footprints used in the Hazus loss model were converted to centroids. Note this excludes building footprints that represent floating structures, non-building structures, and smaller structures. Simple overlays were done to develop summary statistics on a per-hexagonal cell. Cells with no buildings were deleted. Permanent residents (based on 2010 US Census data) per 20-acre cell determined in a similar manner: Summarize the number of permanent residents per building in the 20-acre cell. Note these are often fractional, due to the method used to distribute US Census population data into individual residential buildings. Residential building count (BldgCount_RES) was limited to the Hazus Occupancy Classes RES1, RES2, and RES3. Oregon Department of Geology and Mineral Industries mailing and physical address

800 NE Oregon Street Suite 965