RESOURCE COLLECTION

Understanding San Francisco's street-level data

An overview of street-related data on the Open Data Portal. This resource page includes information on streets, intersections, parcels, addresses, and other street characteristics

DataSF

The basics

Some of the first datasets on the Open Data Portal focused on San Francisco’s streets and addresses. Many departments help produce this data such as Planning, Building Inspection, the Assessor's Office, and the Department of Technology. This resource collection is not exhaustive but highlights key datasets and concepts related to San Francisco streets. But first, two key concepts:

Centerline network number ("CNN")

The CNN is a unique identifier for every street segment and intersection under the jurisdiction of the City and County of San Francisco. Street segments are represented as lines and intersections are represented as points in our datasets.

Parcels ("APN")

A parcel is a piece of land or a lot (real property) identified by a unique Assessor Parcel Number (APN). In datasets, the APN is frequently referred to as "Block and Lot", "Parcel Number", "Parcel ID", or sometimes abbreviated as "blklot".

  • Note 1: Sometimes taxable parcels are stacked on top of one another, often for condominiums. In these cases you may come across the term "mapblklot". This is the lowest APN in a stack of parcels.
  • Note 2: The City and County of San Francisco has two related but distinct parcel databases. The first is managed by the Department of Public Works, is created by surveyors, and is used in the Department of Public Works basemap. Public Works parcels are used to identify very precisely where private properties end and where public City property begins (e.g. sidewalks, roads, rights of way, etc.). The second is managed by the Assessor-Recorder's Office. Assessor parcels are defined by Revenue and Taxation code and Property Tax law. The Assessor-Recorder uses official maps defined under Revenue and Taxation code section 325 in the creation of assessor parcels and are used to identify taxable property. Each of the Assessor's parcels have an Assessor's Parcel Number (APN) which is used by other departments including but not limited to Tax Collector for tax collection, DBI for permitting, and other use cases.
  • Note 3: Though most parcels are the same between Public Works and the Assessor’s Office, they are not a perfect match.

Always review a dataset's metadata before using a dataset and reach out to support@datasf.org with any questions.

Resources

Parcels, building footprints, and land use

Parcels – Active and Retired
Parcels are specific pieces of land with clear boundaries that define property ownership. The final records of these parcels are kept by the Office of the Assessor-Recorder. This dataset includes both current and past parcels, each identified by a unique Assessor Parcel Number (APN).
Building footprints
The building footprints for San Francisco and Treasure Island as of 2010. The middle of each building was used to assign a parcel number to the footprint. "mblr" represents the APN in this dataset.
Land Use
This dataset, last updated in 2023, shows how each parcel of land is used. Land use categories include residential, mixed residential, vacant, and retail, among others. Each parcel is identified by its Assessor Parcel Number (APN) and is also referred to as 'mapblklot'.
Assessor Historical Tax Rolls
This dataset includes the Office of the Assessor-Recorder’s secured property tax roll from July 1, 2007, to June 30, 2023. It contains all legally disclosable information, such as property location, property value, a unique property identifier, and specific property characteristics. In this dataset, the Assessor Parcel Number (APN) is referred to as the Parcel Number.