B.1 Buildings Inventory

The 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 Definition

For 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 Layer

The 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 Aspects

The 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 Attributes

Table 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 Attributes

FIELD	TYPE	DESCRIPTION
BUILDING_ID	Long Integer	Unique identification number assigned to each building.
PARCEL_ID	Long Integer	Identification number of the parcel on which the building is located.
APN	Varchar(24)	Tax assessing parcel number of the parcel on which the building is located.
CITY_ID	Integer	SEMCOG identification number of the municipality, or for Detroit, master plan neighborhood, in which the building is located.
BUILD_TYPE	Integer	Building type. Please see section B.3 for a detailed description of the types.
RES_SQFT	Long Integer	Square footage devoted to residential use.
NONRES_SQFT	Long Integer	Square footage devoted to nonresidential activity.
YEAR_BUILT	Integer	Year structure was built. A value of 0 indicates the year built is unknown.
DEMOLISHED	Date	Date structure was demolished.
STORIES	Float(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	Integer	Median height of the building from LiDAR surveys, NULL if unknown.
HOUSING_UNITS	Integer	Number of residential housing units in the building.
GQCAP	Integer	Maximum number of group quarters residents, if any.
SOURCE	Varchar(10)	Source of footprint polygon: NEARMAP, OAKLAND, SANBORN, SEMCOG or AUTOMATIC.
ADDRESS	Varchar(100)	Street address of the building.
ZIPCODE	Varchar(5)	USPS postal code for the building address.
REF_NAME	Varchar(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.

ADDRESS

Buildings with addresses on multiple streets will have each street address separated by the “ | “ symbol within the field.

B.3 Building Types

Each 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 Types

The 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 Types

The 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 Assignments

Buildings 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 Types

BUILD TYPE	DESCRIPTION	NAICS SECTORS	RGB
11	Educational	611	190-232-255
13	Religious and Civic	813	0-132-168
14	Governmental	921-928	0-76-115
21	Retail Building	441-454, 811-812	255-190-190
23	Office Building	511-551, 561	255-0-0
31	Manufacturing	311-339	194-158-215
32	Wholesale Trade	423-425	170-102-205
33	Warehouse and Storage	493	112-68-137
41	Transportation and Utility	221, 481-488, 562	204-204-204
42	Delivery Services	491-492	156-156-156
51	Health and Social Services	621, 624	214-157-188
52	Hospital	622	245-122-182
53	Residential Care Facility	623	137-68-101
61	Leisure Activity	711-713	137-205-102
63	Hotel and Motel	721	209-255-115
65	Eating and Drinking	722	85-255-0
71	Agricultural	111-213	255-255-0
81	Single-Family Housing	Residential	255-211-127
82	Attached Condo Building	Residential	230-152-0
83	Multi-Family Apartment	Residential	137-112-68
84	Mobile Home	Residential	137-68-68
91	Movie Theater	51213	168-0-0
92	Library	51912	0-197-255
93	Dormitory Quarters	72131	92-137-68
94	Funeral Services	81220	255-127-127
95	Parking Garage	81293	78-78-78