Boundary

Visual, Precise, Accurate Boundaries

Enhance your business processes with highly accurate location information for various map-oriented applications including listing portals, research tools, business intelligence mapping, public safety, and demographic applications. ATTOM has the most extensive boundary data for more than 155 million properties nationwide with flexible delivery solutions, such as APIs, bulk files, match & append, and more.

Types of Boundaries

Properties are defined by a parcel boundary that establishes its location and dimensions. We may choose to group properties at various levels based on commonly accepted geographic areas such as states, counties, and neighborhoods. Our analysis of properties may include the addition of data that is specific to a geographic area. The following are some of the different geographic areas (boundaries) available within ATTOM Cloud

• Economic Boundaries (including Census)
• Hazard Boundaries
• Neighborhood Boundaries
• Political Boundaries
• Postal Boundaries
• School Boundaries

Boundary Data

Profile: For each boundary such as a county or school district, we may have profile data that defines various characteristics of that area. Within ATTOM Cloud, these are usually represented by dimension tables such as DimCounty, DimPlace, DimSchoolDistrict.

Shape: A geographic area is usually defined as a collection of one or more shapes consisting of interconnected coordinates. These can be defined using two-dimensional or 3-dimensional coordinate systems. These shape definitions can be used to visually represent the geographic area as well as provide the basis to establish which points fall within the area, or which other geographic areas overlap. e.g. which zip codes fall within the boundaries of a county. A planned enhancement to ATTOM Cloud will make these shape files available. Boundaries are available via ATTOM API and bulk file delivery.

Property To Boundary: Lookup data used to establish which geographic areas are associated with a property. ATTOM Cloud provides several options for property matching. The PropertyGeodata table contains geocodes for commonly used geographic areas. PropertyBoundaryMatch provides a more comprehensive lookup matching properties to many geographic areas. PropertySchoolMatch is used to match properties to schools based on school district assigned attendance zones and by specific grades.

Datasets

The following are the Boundary datasets. These datasets can be purchased individually for any combination of geographies such as state or county. The datasets have also been combined with other data into solution packs.

Census Block

The smallest geographic unit used by the US Census Bureau for publishing census and other demographic/economic data. Each census block is bounded by visible features such as streets, roads, rivers, and railroad tracks along with nonvisible boundaries such as property lines, cities and townships, school districts, and counties.

Census Block Group

A geographic unit used by the US Census Bureau for publishing census and other demographic/economic data. It consists of a cluster of blocks within the same census tract. Each census block group is usually a contiguous area and never crosses tract, county, or state boundaries.

Census Tract

A geographic unit used by the US Census Bureau for publishing census and other demographic/economic data. They are small, relatively permanent subdivisions of a county. Census tracts generally have a population between 1,200 and 8,000 people. The boundaries are chosen with the intention of being maintained over a long period of time to assist with the analysis of statistical trends.

Congressional District

Political boundaries are used in federal elections for the selection of congressional representatives. There are a total of 435 congressional districts divided amongst the states based on decennial census populations. Each state is guaranteed to have at least one congressional district. Each state legislature has the authority to determine how its state is to be broken into congressional districts. 

County

A county is the largest territorial division for local government in the US. There are a total of 3,144 counties. in the US

FEMA Flood

As part of the National Flood Insurance Program, the Federal Emergency Management Agency (FEMA) publish information about flood risk by dissecting the US into 72,000 areas. These are known as FIRM Panels and FIRMettes - Flood Insurance Rate Maps (FIRM). Each FIRM Panel identifies areas (flood zones) in which there is a specific risk of flooding.

Parcel Boundary

A property can be thought of in two ways. A single point is defined by a longitude and latitude that represents the centroid of the property, or by a boundary that defines the outer perimeter of the property. Parcel maps define the official boundaries for each property within a county to ensure there are no disputes over ownership of the land contained within.

Place

Census places are geographical areas defined by the US Census Bureau that include both Incorporated Places and Census Designated Places (CDPs). Incorporated Places are legally bounded entities established by the government in each state, including cities, towns, villages, and boroughs. CDPs are statistical entities defined in the absence of Incorporated Places as a way of accumulating data in areas with settled populations.

Postal City

A Postal City is the name of the town or city having a central post office responsible for the delivery of mail to its residents. This may not be the name that residents consider themselves to reside in.

Residential Neighborhoods

Residential neighborhoods are geographical areas considered to have similarities in their demographics and housing. Other factors influencing the definition of neighborhoods include local government planning, law enforcement, and transportation. Their use is not consistent across counties. Up to three levels of a neighborhood can be defined. These levels can be identified by the geography type key assigned.

School Attendance Area

A school attendance area is a reference to a boundary defining the properties zoned to attend a specific school. The attendance area will vary by grade to reflect the different types of schools servicing the neighborhood.

School District

US schools are usually grouped into school districts responsible for administering those schools. Some school districts may be responsible for all K12 schools in an area, while others may only administer schools of a specific level (e.g. high schools). This dataset provides a summary for each of those school districts. This dataset provides the mechanisms to establish the relationships between individual properties and a school district

Subdivision

Each county can consist of one or more county subdivisions. These can be either Minor Civil Divisions (MCDs) or Census County Divisions (MCDs). A county cannot have both. An MCD has legal boundaries and names as well as a government or administrative purpose defined by State law. CCDs are statistical entities established cooperatively by the US Census Bureau and State/local government.

Zip Code

Zip codes were developed by USPS as a way to assist in the processing and delivery of mail. Each USPS delivery point is assigned to one of ~33,000 5-digit zip codes.

Zip Code Tabulation Area

Zip Code Tabulation Areas (ZCTAs) are a representation of the USPS Zip Codes defined by the US Census Bureau. They are formulated by looking at all the Census Blocks that are associated with a Zip Code. Where a Census Block spans multiple Zip Codes, it is assigned to the ZCTA having the most addresses.