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###This is a developing exploratory map identifying


The SanGIS parcel layers are “stacked” parcels. That means that for any piece of ground there may be multiple parcels. For example, a condominium building in downtown San Diego may have 200 individual condos. Each condo is a separate taxable parcel. All 200 parcels will be associated with the same physical lot on the ground. When the SanGIS parcel layer is created each individual condo has a polygon representing the physical location of the parent parcel. In this example there will be 200 polygons all stacked on top of each other that represent the taxable parcels and each polygon will have the same physical characteristics (shape, size, area, location) – they are, essentially, copies of each other. However, other associated information (owner, document numbers, etc.) will be different for each. In this case, each condo unit will have its own parcel number and there will be no single parcel representing the lot on the ground.

Besides condominiums there are two other cases where you will see stacked parcels – possessory interests and mobile homes. Possessory interest parcel numbers (APNs) start with 76x. A possessory interest (or PI) parcel represents a taxable interest in the underlying, or parent, parcel but not necessarily ownership. For instance, a private company may have an arrangement with a University to operate a business on campus – a coffee shop or gift shop for example. The private business is taxable and is assigned a 76x APN that is associated with the parent parcel owned by the University. Possessory Interests do not represent ownership on the parcel, only a taxable interest in the underlying parent.

Mobile home parcel APNs start with 77x. In a manner similar to the possessory interests, mobile home owners own their home (coach) but not the underlying property on which the house sits. The actual mobile home is a separate taxable parcel associated with the mobile home park parent parcel. These taxable parcels all have the same polygon as the underlying parent parcel and will show as stacked parcels as well.


  • There may be inaccuracies with the County Data

###Next Steps

  • Perform a City by City analysis of stacked properties comparing percentage of lots.
  • Many properties are listed as Condo-Conversions, which could help in determining properties that were once rent-controlled and Ellis'd (in cities where RSOs are implemented)
  • Have a question? Email me, or shoot me a tweet @theworksla