Geo Codes

Dataset

Description

Places properties within geographic areas so that property data can be grouped into geographic areas and/or property data can be combined with geographic data such as crime, demographics, and sales trends.

Usage

Property Analysis: Trends in property markets can be cross-referenced with boundary data.

Property Portals: Information specific about the property can be combined with boundary data such as climate, climate risk, crime, demographics, natural disasters, and schools.

Sourcing

ATTOM has an extensive library of boundary shapefiles that allow us to determine which properties fall within which boundaries. We are in a good position to do the billions of calculations necessary to match properties to boundaries. We have stored the results for many of the commonly used boundaries to provide a simple, convenient lookup table that can be used to match properties to these boundaries.

Tables/Views

A series of tables and views are available within ATTOM Cloud to assist in matching properties to geographic areas and/or locating all the properties in a geographic area.

Note: The following table should be used to establish the best source for matching a property to a specific geography.

DimCounty

Provides information about a county, as well as matching counties to geographic areas such as MSAs and CBSAs that are aggregates of individual counties.

Use the field CountyKey to connect a property in PropertyAddresses to DimCounty

DimTract

Provides a translation between the external codes/names used by the US Census Department and the internal codes used by ATTOM Cloud. to identify a census

PropertyAddresses

Provides information used to identify and locate properties as well as some of the most frequently used geographic boundaries applicable to the property. The following geography types are identified for each property in this table: -

• Congressional District
• County
• Jurisdiction
• MSA
• Neighborhood
• Postal City
• State
• Subdivision
• Township
• Zip Code

PropertyGeoData

Cross-reference table providing the identity of commonly used geographic boundaries matched to a property. The following geography types are identified for each property in this table: -

• Census Block
• Census Block Group
• Census Tract
• Census FIPS Place
• CBSA
• Minor Civil Division
• MSA

Rows: 16 million
Columns: 15
Family: Property

PropertyBoundaryMatch

A comprehensive cross-reference table that matches properties to geographic boundaries. This table can also be used to identify all the properties that fall within a specific geographic boundary.

Rows: 272 million
Columns: 4
Family: Property

The PropertyBoundaryMatch has three key fields:

1. GeogrpahyTypeKey - The type of geography being cross-referenced e.g. 53 - School District  (use DimGeographyType for a list of values)
2. ATTOM ID - The unique property identifier used by ATTOM to identify a property (This is found in all property-centric records within ATTOM CLoud)
3. GeographyKey - The unique identifier for one or more geographic areas that overlap with the property

The following is an example of using PropertyBoundaryMatch to match a property to FEMA flood zone

/*
 * Identify all simgle family residences in a specific county (Duval, FL) that are in the "A" or "X" Flood Zones (>= 1% Chance of flooding)
 * A - 1% Chance of flooding based upon approximations
 * AE - 1% Chance of flooding based on details analysis
 * AO - 1% Chance of shallow flooding from sheet flow
 * A99 - 1% Chance of flooding but will be protected by construction work underway
 * X - >1% Chance of flooding
 */
SELECT
	pa.[ATTOM ID] ,
	pa.SitusAddress,
	pa.SitusCity,
	pa.SitusZip,
	pa.SitusState,
	dfh.zonetype
	
From adw.PropertyAddresses pa
Left Join adw.DimPropertyType dpt on pa.PropertyTypeKey = dpt.PropertyTypeKey 
Left join adw.PropertyBoundaryMatch pbm on pa.[ATTOM ID] = pbm.[ATTOM ID] 
Left Join adw.DimFEMAFloodHazard dfh on pbm.GeographyKey = dfh.FEMAFloodHazardKey 

Where pa.CountyKey = 35964 And dpt.SubCategory = 'SINGLE FAMILY RESIDENCE' And pbm.geographyTypeKey = 40 And dfh.zonetype in ('A','AE','AO','A99','X')

Order By pa.SitusZip

Dimension Tables

The following dimension tables are relevant to Geo Code data, providing information about each level of aggregation for the data

DimBlock: Details for each of the ~11 million Census Blocks assigned to properties by the US Census Bureau

DimBlockGroup: Details for each of the ~240,000 Block Groups assigned to properties by the US Census Bureau. Block Groups are grouped into Tracts and Subdivisions.

DimCongressionalDistrict: Description of each of the 435 US Congressional Districts.

DimCounty: Description of each of the ~3,100 counties/parishes in which properties can be located. Counties are grouped into CBSs and States.

DimCountySubdivision: Details about each of the ~36,000 County Subdivisions that make us each County.

DimFEMAFloodHazard: Represents each of the ~ 4.2 million flood zones defined by FEMA, each representing an area with a specific probability of flood.

DimGeographType: The complete list of geography types used as boundaries as well as the dimension table used to provide details about each boundary

DimJurisdiction: Details about each of the ~5,000 jurisdictions that play some role in the administration of US properties.

DimNeighborhood: Details about each of the ~750,000 local neighborhoods to which many properties belong.

DimPlace: A list of ~32,000 place names 

DimPostalCity: A list of the ~275,000 postal cities USPS have defined and to which most non-rural properties belong

DimSchoolAttendanceArea: A list of the ~440,000 school attendance areas used to match properties to one or more assigned schools for a specific grade

DimSchoolDistrict: Details about the ~20,000 school districts serving the educational needs of resdidents.

DimTract: Details about each of the ~85,000 Census Tracts assigned to the US Census Department to a property. Census Tracts are grouped into Counties.

DimZipCode: A list of the ~33,000 zipcodes assigned by USPS to facilitate the delivery of mail to properties across the USA.

DimZipCodeTabulationArea: A list of the ~33,000 zipcode tabulation areas assigned by the Census Bureau that aggregate Census Blocks that closely align to posytal zipcodes

Matching Data

ATTOM ID

Because there is not a universally accepted standard for property identification (like the use of SSN to identify US citizens), properties can be difficult to identify. Alternatives such as APN or street address can change over time and they often lack a consistent way of being formatted. ATTOM addresses this by assigning a single, permanent identifier to each property in the form of a very precise number (integer). The use of a number can assist in making SQL queries run faster.

GeographyTypeKey

A unique code is used to identify each class of boundary. e.g. 35 = Congressional District. When using a table such as PropertyBoundaryMatch, it is usually necessary to provide the PropertyTypeKey to make it clear what type of geography is being matched/searched.

GeographyKey

A unique number is assigned to each boundary of a specific class (geography type). For example, each Census Block has been assigned an ATTOM identifier separate from the numbers assigned by the US Census Department. Being a number, the performance of queries against millions of records ATTOM Cloud data can be dramatically improved. The geography key for a specific geography type is unique only within that geography type. The names used for geography keys in ATTOM Cloud tables vary but usually contain the suffix Key.

GeoID

In addition to GeographyKey, ATTOM also makes use of a GeoID. This is a 32-character string that uniquely identifies each and every geographical area regardless of its type. There are many cases in which both a GrographyKey and a GeoID are available to match properties to a geographic area. ATTOM leaves it to your discretion as to which option is used. The GeoID should be thought of as being the geography equivalent of an ATTOM ID.

Geography Codes

Codes are yet another way to identify geography. Typically, these are values adopted by external sources of the data. They are provided to facilitate the matching of ATTOM Cloud data with data sourced from other places. The names vary, but usually contain the suffix Code.

Example

Product Articles (P-Articles)

All solution packs containing the Geo Code data element will include the following p-articles to help you understand and use the data: -

• Property Boundary Matching