B.1 Buildings InventoryThe Building Footprints data layer is an inventory of buildings in Southeast Michigan representing both the shape of the building and attributes related to the location, size, and use of the structure. The layer was first developed in 2010using heads-up digitizing to trace the outlines of buildings from 2010 one foot resolution aerial photography. This process was later repeated using six inch resolution imagery in 2015 and 2020 to add recently constructed buildings to the inventory. Due to differences in spatial accuracy between the 2010 imagery and later imagery sources, footprint polygons delineated in 2010 may appear shifted compared with imagery that is more recent.Building DefinitionFor the purposes of this data layer, a building is defined as a structure containing one or more housing units AND/OR at least 250 square feet of nonresidential job space. Detached garages, pole barns, utility sheds, and most structures on agricultural or recreational land uses are therefore not considered buildings as they do not contain housing units or dedicated nonresidential job space.How Current is the Buildings Footprints LayerThe building footprints data layer is current as of April, 2020. This date was chose to align with the timing of the 2020 Decennial Census, so that accurate comparisons of housing unit change can be made to evaluate the quality of Census data.Temporal AspectsThe building footprints data layer is designed to be temporal in nature, so that an accurate inventory of buildings at any point in time since the origination of the layer in April 2010 can be visualized. To facilitate this, when existing buildings are demolished the demolition date is recorded but they are not removed from the inventory. To view only current buildings, you must filter the data layer using the expression, WHERE DEMOLISHED IS NULL.B.2 Building Footprints AttributesTable B-1 list the current attributes of the building footprints data layer. Additional information about certain fields follows the attribute list.Table B-1 Building Footprints AttributesFIELDTYPEDESCRIPTIONBUILDING_IDLong IntegerUnique identification number assigned to each building.PARCEL_IDLong IntegerIdentification number of the parcel on which the building is located.APNVarchar(24)Tax assessing parcel number of the parcel on which the building is located.CITY_IDIntegerSEMCOG identification number of the municipality, or for Detroit, master plan neighborhood, in which the building is located.BUILD_TYPEIntegerBuilding type. Please see section B.3 for a detailed description of the types.RES_SQFTLong IntegerSquare footage devoted to residential use. NONRES_SQFTLong IntegerSquare footage devoted to nonresidential activity.YEAR_BUILTIntegerYear structure was built. A value of 0 indicates the year built is unknown.DEMOLISHEDDateDate structure was demolished. STORIESFloat(5.2)Number of stories. For single-family residential this number is expressed in quarter fractions from 1 to 3 stories: 1.00, 1.25, 1.50, etc.MEDIAN_HGT IntegerMedian height of the building from LiDAR surveys, NULL if unknown.HOUSING_UNITSIntegerNumber of residential housing units in the building.GQCAPIntegerMaximum number of group quarters residents, if any.SOURCE Varchar(10)Source of footprint polygon: NEARMAP, OAKLAND, SANBORN, SEMCOG or AUTOMATIC.ADDRESSVarchar(100)Street address of the building.ZIPCODEVarchar(5)USPS postal code for the building address.REF_NAMEVarchar(40)Owner or business name of the building, if known.CITY_ID Please refer to the SEMCOG CITY_ID Code List for a list identifying the code for each municipality AND City of Detroit master plan neighborhood.RES_SQFT and NONRES_SQFT Square footage evenly divisible by 100 is an estimate, based on size and/or type of building, where the true value is unknown.SOURCE Footprints from OAKLAND County are derived from 2016 EagleView imagery. Footprints from SEMCOG are edits of shapes from another source. AUTOMATIC footprints are those created by algorithm to represent mobile homes in manufactured housing parks.ADDRESSBuildings with addresses on multiple streets will have each street address separated by the "
" symbol within the field.B.3 Building TypesEach building footprint is assigned one of 26 building types to represent how the structure is currently being used. The overwhelming majority of buildings (86.9%) are single-family residential.Nonresidential TypesThe 22 nonresidential building types are based on the 2017 North American Industrial Classification System (NAICS), which classifies establishments based on economic activity. Each of the building types represent one or more 3-digit NAICS sector groupings, except for five special building types that do not fit well within this system. These special types (movie theaters, libraries, dormitories, funeral services, and parking garages) have land use AND/OR trip generation characteristics that differ substantially from other types of activity in their respective NAICS sector and are therefore classified individually. More information on NAICS, including descriptions of the economic activity sectors, can be found at the Census Bureau's NAICS web site.Residential TypesThe four residential building types are based on a combination of units in structure, and ownership. Single-Family Housing are homes and site condominiums that contain one housing unit. Most are owned individually, but there are instances of groups of homes owned by a housing commission for rent. Traditional duplexes where each unit is owned by the same entity are also classified as single-family housing.Attached Condo Housing are buildings which contain two or more housing units, each of which shares one or more walls with an adjoining unit and can be independently owned. Multi-Family Apartment buildings contain three or more units, all of which are owned by a single entity and intended as rental units. Mobile Homes are pre-manufactured housing located primarily in manufactured housing parks.Building Type AssignmentsBuildings are classified primarily on the economic sector of the property owner. Therefore, each building on a site will typically have the same building type assigned. For example, all buildings at an automotive plant will be classified as Manufacturing, even though some small buildings might be typically used as storage. Government owned utility buildings will usually be classified as Utility buildings rather than Governmental. While not ideal for every purpose, it would not be feasible to attempt to uniquely classify nearly two million individual structures, and this method corresponds better to the use of buildings in developing parcel based land use. A description of SEMCOG building types, including the relevant NAICS codes for the type, are found in Table B-2. The RGB color values match SEMCOG's layer symbology for building types.Table B-2 Building TypesBUILD TYPEDESCRIPTIONNAICS SECTORSRGB11Educational611190-232-25513Religious and Civic8130-132-16814Governmental921-9280-76-11521Retail Building441-454, 811-812255-190-19023Office Building511-551, 561255-0-031Manufacturing311-339194-158-21532Wholesale Trade423-425170-102-20533Warehouse and Storage493112-68-13741Transportation and Utility221, 481-488, 562204-204-20442Delivery Services491-492156-156-15651Health and Social Services621, 624214-157-18852Hospital622245-122-18253Residential Care Facility623137-68-10161Leisure Activity711-713137-205-10263Hotel and Motel721209-255-11565Eating and Drinking72285-255-071Agricultural111-213255-255-081Single-Family HousingResidential255-211-12782Attached Condo BuildingResidential230-152-083Multi-Family ApartmentResidential137-112-6884Mobile HomeResidential137-68-6891Movie Theater51213168-0-092Library519120-197-25593Dormitory Quarters7213192-137-6894Funeral Services81220255-127-12795Parking Garage8129378-78-78
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