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

Educational

611

190-232-255

Religious and Civic

813

0-132-168

Governmental

921-928

0-76-115

Retail Building

441-454, 811-812

255-190-190

Office Building

511-551, 561

255-0-0

Manufacturing

311-339

194-158-215

Wholesale Trade

423-425

170-102-205

Warehouse and Storage

493

112-68-137

Transportation and Utility

221, 481-488, 562

204-204-204

Delivery Services

491-492

156-156-156

Health and Social Services

621, 624

214-157-188

Hospital

622

245-122-182

Residential Care Facility

623

137-68-101

Leisure Activity

711-713

137-205-102

Hotel and Motel

721

209-255-115

Eating and Drinking

722

85-255-0

Agricultural

111-213

255-255-0

Single-Family Housing

Residential

255-211-127

Attached Condo Building

Residential

230-152-0

Multi-Family Apartment

Residential

137-112-68

Mobile Home

Residential

137-68-68

Movie Theater

51213

168-0-0

Library

51912

0-197-255

Dormitory Quarters

72131

92-137-68

Funeral Services

81220

255-127-127

Parking Garage

81293

78-78-78

Showcases featuring Building Footprints, 2020