Parcel vs. Assessment Relationship

Introduction

A common misconception is that a parcel has a one-to-one relationship with an assessment record. In many cases that is correct, however, there are many times where this is not the case and you will need to adjust your logic when the parcel has a one-to-many relationship to the assessment records.

Scenario

A parcel has a one-to-many relationship when there are multiple owners in separate taxable units of a single parcel. For example, a condominium complex where the single parcel boundary encompasses 50 condominiums, each owned and taxed separately. In this scenario, there is a single parcel but 50 assessment records.

Common Property Types 

One-to-one relationship

Property types where a one-to-one relationship is the common occurrence are:

• Single Family Residence
• Multi Family Residence
• Commercial Properties
• Industrial Properties
• Vacant Land Properties

Many-to-one relationship

Property types where a one-to-many relationship is the common occurrence are: 

• Condominiums
• Mobile Home Parks
• High-rise Apartments where units are individually owned
• Time-shares  

The property highlighted below has a property type of "condominium," with 119 related assessment records associated with it, i.e, a single parcel with many assessment records. 

Best Practices API

Identification from a Parcel API Response

The Parcel API response will carry a field that indicates if there are multiple related assessment records. 

A top-level object from the parcel result is "related." This object provides information on objects that are related to the subject parcel. In the case of many related assessment records, the count is identified in the parcel[0].related.associatePropertyCount. 

}
    parcles: [
        {
             "related": {
                  "associatePropertyCount": 119
             },
        }
   ]
}

When the count is greater than 0 and you want to return all the assessment records for the parcel, you can use the Assessment API endpoint /assessments/_on/parcel/{countryCode}/{id} with the LightBox Parcel ID.

From a Geocode Result

A typical workflow is to call the geocode with the address string. From the geocode response you can receive a reference to an assessment record, a parcel record, and a structure record.

If you are only looking for the attribution then it is recommended to use the assessment endpoint to ensure that you have the assessment record that matches the address.

If access to the parcel boundary is needed, you can always make two calls using the parcel endpoint and the assessment endpoint.

From a common map control and identify

When using a map interface, a suggested best practice is to follow these steps:

1. Use the Parcel API Tile endpoint to add parcel tiles to the map.
2. Add a map event to listen for a click event to your map.
3. When a click event occurs, use the latitude and longitude to generate a WKT.
4. Use the parcel/{countryCode}/geometry endpoint to return the parcel record that intersects with the click location.
5. Use the geometry returned to create a geometry object and add it to the map using your map control API.
6. Popup a card that displays the base information.
   1. If the property has several associated assessment records then add a link to the card with a message that states there are related property records.
      1. When the link is activated, make a call to the /assessments/_on/parcel/{countryCode}/{id} endpoint passing in the LightBox Parcel ID and display a select box with the location address information as the text.
      2. Allow the user to select the target property, and make a call to /assessments/{countryCode}/id using the LightBox Assessment ID to return the information for that property.
   2. If the property does not have associated assessment records, there is nothing more to do.

Best Practices SmartFabric

The SmartFabric Core and SmartFabric Premium packages handle this for you by joining each tax record to its own parcel polygon. This creates a stack of the same parcel at that location. If a condominium has 50 units then the parcel will be replicated (stacked) 50 times.

The data is modeled differently with SmartFabric Professional and SmartFabric Core. In these products, they will model the the condo parcel as a single parcel record. On that parcel record is an attribute that will provide the number of related parcels. 

In this example, the ASSOCIATED_ASSESSMENT_COUNT would have a value of 50. 

You would then need to go through the ParcelAssessentRelation table using the PARCEL_LID to retrieve the related records.

More Information

• LightBox Assessment
• LightBox Parcel Boundaries
• Parcel to Assessment matching