FAQ: Parcel Data Coverage and Nuances

SmartParcels provides the parcel boundary data for the LightBox Valuation Research application. SmartParcels is the most complete parcel database on the market, combining parcel boundaries with 300+ property attributes to help you make more confident decisions.

Coverage

• US

  • Over 97% of US counties

  • More than 95% of US parcels (145+ million parcel boundaries)

  • Parcel data covers over 99% of the US population

• US Territories

  • First to bring US territory data to the market

  • Parcel data for 85 of 86 (98.8%) municipalities in Puerto Rico, U.S. Virgin Islands, Guam, and Northern Mariana Islands, representing more than 99% of parcel boundaries
    
    

Question: Why are some parcels lacking property attribution?

Answer: Parcel boundaries are often maintained and provided by a separate entity than property attribution. Parcels are frequently maintained by an entity, such as the county GIS, survey, or public works team while the attributes are maintained by the county assessor. These two entities generally release their content at different times.

LightBox obtains parcel boundaries and assessor attribution as quickly as possible and then links the parcel boundaries to the attribution. While the LightBox team is the gold standard in the industry for this process, linking may not be perfect in these scenarios:

• Different data vintages. For example, if parcel boundaries are newer than the assessor attribution. In this scenario, parcel boundaries may exist that have not yet appeared in the assessor data. These parcels have no assessor attribution to link to.

• Parcel data is missing information to link to attribution. We leverage parcel attribution such as parcel identification numbers to link to the property information. These values are not always present. There are also scenarios where parcels are digitized from a physical source and therefore have no attribution to leverage for linking to assessor attribution.

Question: Are parcels edge matched?

Answer: It is possible that in some circumstances parcel overlaps or gaps may exist. The parcel boundaries that you receive are provided by each county. Since each county is the subject matter expert within each of their respective jurisdictions, we rely on them for the alignment of the parcels. Enforcement of topology rules to permit or prohibit slivers, gaps, etc. is determined by each county.

Question: Why are there parcel stacks?

Answer: Parcel stacks (multiple pieces of parcel geometry in the same physical location) may periodically exist. These stacks may occur due to these possible scenarios:

• The relationship between parcel boundaries and property attributes is a “many-to-one” relationship. Condominiums, timeshares, and mobile home parks usually have a single parcel containing multiple taxable properties. (See figure 1a below). When LightBox links these taxable properties to the single parcel, the result is a “stack” of parcels—each associated with the individual properties. (See figure 1b). When this occurs, each parcel in the stack will have the same Parcel ID but will have unique tax assessor ID values.

Figure 1a: many-to-one relationship with multiple properties on one parcel.

Figure 1b: result of a many-to-one join. Note: identical parcel IDs but different Tax Assessor IDs. 

b. Stacks may be present in the parcel content provided by the county.

In some circumstances, the parcel boundary data provided for the county may arrive with stacks already present in the data. LightBox does not alter the parcel structure after provisioned by the county. So, if stacks exist in the source data, they will exist in the data you receive.

One thing to note is that the relationship between assessor property record/attribution and parcels will be one-to-one if the stack was present in the source data.