Parcel boundaries are fundamentally important in real estate. Without boundary lines, there’s nothing to define the property and thus nothing to own or to sell.
A parcel boundary is also a key starting point when aggregating property data. Without precisely drawn parcel lines, the data has no frame of reference.
So, without first establishing accurate parcel boundaries, all subsequent data compiled on the properties can be misleading.
Parcel boundary lines are used with other data to:
- Create user friendly maps;
- Guage the risk of floods and other hazards;
- Compare nearby properties for sale;
- Produce professional marketing pamphlets and reports for clients.
Due to their importance, ATTOM invests heavily in digitizing accurate parcel boundaries in the U.S., employing an in-house team of geographic information system (GIS) experts to draw and regularly verify parcel boundaries.
What is a US parcel boundary?
With the widespread availability of digital maps, it has become easier to find parcel boundaries and use them with other data sets.
That work is based on old concepts, and so it’s worth reviewing some basic terms, starting with what is a parcel boundary?
A parcel boundary defines the dimensions and shape of a piece of land where homes, apartments, shops, offices and vacant land can be located.
The lines on all sides of the parcel are known as its “boundaries” or “boundary lines.” Boundary lines separate one parcel from another property.
Among its lines, the property’s “frontage” is often especially important in determining the land’s value. “Frontage” generally refers to the width of the property as measured at the front of the property, but it can also refer to the strip of land bordering a street, lakefront or oceanside. The sides of the property are sometimes referred to as “side property lines.”
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How are US parcel boundaries established?
Licensed surveyors determine boundary lines using measurements and historical records. A survey is needed to produce a survey map and a plat map, both of which are frequently used in real estate deals and land development, as well as to settle legal disputes among neighbors or prevent future disputes near property lines.
A survey map will contain the parcel boundary lines and improvements, like fences, a garage, a septic tank, and so on. The map often shows any easements, such as a shared driveway where another property owner has the right to use a portion of the land. Also, it can reveal any property encroachments where, say, a neighbor has built a fence or other structures on a portion of the property without permission.
Plat maps typically show multiple property boundaries, as well as streets, flood zones and areas where a utility has the right to use private property to install and maintain services.
Plat and survey maps are often available online through a county website; however, not all counties have online maps available. The county websites can also be difficult to use, particularly if you are researching multiple properties in an area. Also, sometimes county parcel records are only periodically updated, and it may be unclear from the website when the parcel’s boundaries were last verified.
What happens when a US parcel is subdivided?
U.S. parcel boundaries do change. Developers frequently split large parcels into several plots to build homes, condos, or shops and offices. Small tracts of land containing a single home can also be split or modified by the owner.
When subdividing the property, the boundary lines are redrawn. Each parcel will have its own title and can be sold separately.
Properties are subdivided or modified more often than people think, and real estate professionals should keep this in mind when working with online property data.
It is essential for a data aggregation company to verify and update the parcel boundaries to ensure the boundary lines have not changed. ATTOM’s in-house GIS team, for example, updates the property data monthly, and each boundary line is verified on average every six months and at least once a year.
Where to get a US parcel boundary?
To research parcel boundary lines, you once had to take a trip to city hall or the county offices and, sometimes, walk the property and look for stakes in the ground.
Surveyors still do that legwork to complete surveys and maps. Today, however, most U.S. parcel boundaries have been digitized and are available online, making it much easier for the owners and real estate professionals to find accurate property boundaries.
ATTOM, for example, has a database of 155 million parcel boundaries in the U.S. and in portions of Canada, an area representing about 99% of the U.S. population. The company also has digitized 187 million building footprints that lie within the parcels.
How to find properties with US parcel data?
With digitization, it is far easier to find and view a parcel almost anywhere in the U.S.
You can search for the property in various ways, by address, owner’s name, assessor parcel number, tax or listing ID.
Digitization also makes it much easier to customize maps using parcel boundaries in tandem with other boundary data sets.
For example, a digital map can indicate where the closest schools, shops and services are located, and what roads serve the area, thereby revealing the neighborhood, its density and traffic patterns.
You can superimpose Federal Emergency Management Agency flood maps, showing if the property’s boundary lines cross designated flood zones. A parcel boundary can be placed on a topographical map, showing elevations and physical land features, such as nearby hills, streams and lakes.
How to find my parcel boundary and property lines?
ATTOM offers two levels of data on parcel boundaries. The basic service provides a file with the parcel shapes, an indexing file and property identification codes, including an ATTOM ID, an assessor parcel number (APN code) and a FIPS code (the five number code that identifies the geographic area of the property).
With the plus service, ATTOM will additionally provide the parcel address, ownership information, last sale available and key property characteristics.
Parcel boundaries are also available on ATTOM Cloud, which is an easy and fast way to gain insights on roughly 155 million U.S. properties. ATTOM Cloud is a good option for companies that don’t want to maintain a large database. The service is also flexible, enabling companies to access only specific datasets and geographies that they need.
ATTOM has the most comprehensive database of U.S. property boundaries. And importantly these property lines are updated regularly to ensure its clients are working with the most accurate and detailed datasets in the marketplace.
Written by: Kara Taylor