Building footprints for Clackamas, Multnomah, and Washington Counties, Oregon

Oregon Department of Geology and Mineral Industries 2018 Building footprints 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/ Building footprint delineate the outline of a building or structure. Location and dimensions of structures, including buildings. Dimensions can be used to establish building square footage, or offer a quality check on square footage derived from other sources. Building footprint, in combination with lidar-derived elevation models, can be used to derive building height and if needed, number of stories. Building footprints place a structure relative to a natural hazard or other structures. Buildings, strictly defined, are structures with a roof and walls, and is intended for continuous human occupancy. Building footprints in this database include various non-building structures such as water towers, wharves, gas station canopies, carports, and hayracks. 2018 Complete None planned -123.393783 -121.699969 45.806414 44.871502 ISO 19115 Topic Category geoscientificinformation structure Oregon Geospatial Enterprise Office Metadata Keyword Thesaurus building 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 Structures marked as 'building, modeled': good accuracy, but designed by not being in another category. Structures designed as not modeled, due to their being less than 400 square foot: fully accurate. Structures marked as 'floating' - verified via visual inspection, high accuracy, as we inspected likely locations of such structures on major rivers and lakes. Non-building structures: fair to good accuracy. Parking garages, though by definition a non-building structure, were designated as a building, per FEMA Hazus convention. As we visually inspected areas, we marked carports as non-building structures, but the identification of carports was not systematic. Many carports are likely identified as a building. Water towers and reservoirs were identified by querying for circular geometries: perim/(2*3.14*(sqrt(area/3.14))). Hoop houses and other ancillary agriculture-related structures were systematically surveyed for in agricultural areas, though modest hoop houses in residential areas may not have been identified. Dams and docks were identified visually and systematically by traversing large rivers and lakes. Tank farms in the Critical Energy Infrastructure Hub and major port areas were visually inspected and manually designed as non-building structures. Building footprint outline ideally designates a single building. We attempted to distinguish contiguous buildings that were built at different times and with different material, by dividing up existing larger building footprints. Where encountered, large building complexes were divided up into distinct entities, though the process is limited to orthoimagery and occasional oblique imagery. Add-ons to a building are often difficult to distinguish, and generally associated with the same building. We ran a topology check and fixed all overlapping polygons. Building footprint database was updated to include all buildings in the 3-county area. Building footprints capture a dynamic environment at a point in time. Some buildings present in the database may no longer exist due to fire or teardown. Newer construction, post-2016, may not be present, due to time frame in which we developed the database, and the imagery (orthoimagery and street-level) available for this project. Building footprint outline ideally designates a single building. We attempted to distinguish contiguous buildings that were built at different times and with different material, by dividing up existing larger building footprints. Where encountered, large building complexes were divided up into distinct entities, though the process is limited to orthoimagery and occasional oblique imagery. Add-ons to a building are often difficult to distinguish, and generally associated with the same building. Buildings in the US Highway 26 corridor near Zigzag and Rhododendron do not have building footprints, due to very heavy canopy cover. For loss modeling purposes, we assigned a tax lot centroid to the homes in that area. Such centroids are not present in this file, however. not applicable. Building heights are not provided in this dataset. Metro Regional Land Information System (RLIS) 20160207 Building Footprint Database vector digital data Portland, Oregon Metro Regional Land Information System (RLIS) http://rlisdiscovery.oregonmetro.gov/ 20160205 Oregon Department of Geology and Mineral Industries 2011 Multi-hazard and risk study for the Mount Hood Region, Multnomah, Clackamas, and Hood River Counties, Oregon vector digital data Oregon Department of Geology and Mineral Industries Open-File Report Open-File Report O-11-16 Portland, Oregon Oregon Department of Geology and Mineral Industries 2011 Oregon Department of Geology and Mineral Industries 2013 Landslide hazard and risk study of northwestern Clackamas County, Oregon vector digital data Oregon Department of Geology and Mineral Industries Open-File Report Open-File Report O-13-08 Portland, Oregon Oregon Department of Geology and Mineral Industries 2013 USDA Farm Service Agency 2016 National Agriculture Imagery Program County Compressed Mosaics 2016 raster digital data Washington, D.C. USDA Farm Service Agency https://www.fsa.usda.gov/programs-and-services/aerial-photography/imagery-programs/naip-imagery/ 2016 Building footprint data obtained from Metro RLIS in February 2016. The dataset at the time had a quasi-3d rendering of buildings in the Portland area. We removed the extra geometries by dissolving on the Building ID (BLDG_ID) provided with the data. We then ran topology checks, inspecting for overlapping polygons that plagued the dataset. Newer buildings were added to the RLIS building footprint dataset, but older ones that may have been torn down were not. Often, the same building would be represented two or more times. We cleaned up such topology errors by visual inspection with available orthoimagery. Buildings were digitized by DOGAMI using lidar-derived hillshade imagery, and their present-day existence was confirmed using available orthoimagery. New buildings were attributed as building or a non-building structure based on interpretation of orthoimagery oblique imagery. Most of the digitization activity was concentrated in western portions of Washington County and southwest Clackamas County, where no building footprints were present in the Metro database. Other structures were digitized as quality checks suggested a missing building - for example, a tax lot which contained an improvement value, but no building footprint was associated with that tax lot. Building digitization was done during July - December, 2016, and used latest lidar and orthoimagery available at the time. We systematically examined for floating structures along major waterways and waterbodies, non-building structures in predominately agricultural areas, and water towers and reservoirs by querying for circular geometries. Such structures were manually attributed as such (see Attributes) Once in place, a building ID was assigned to each footprint. Clackamas County range: 1 - 199,999 Multnomah County range: 200,000 - 499,999 Washington County range: 500,000 - 710,000. Topology and attribute consistency checks were performed. We did not add a square footage attribute, as the projection and the format (feature class) auto-supplies and updates such information in the SHAPE_Area attribute. Oregon Department of Geology and Mineral Industries mailing and physical address

800 NE Oregon Street Suite 965