> For the complete documentation index, see [llms.txt](https://sfdigitalservices.gitbook.io/data-standards-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sfdigitalservices.gitbook.io/data-standards-guide/standard-reference-data/basemap/parcels.md). # Parcels ## Definition * A parcel is a piece of land or a lot (real property) identified by a unique Assessor Parcel Number (APN) * The APN is comprised of a **block number** and a **lot number** * Block number format: 4 numerical digits + 1 optional letter character (0012A) * Lot number format: 3 numerical digits + 1 optional letter character (037B) * Blocks are groupings of lots which are usually contiguous and usually bounded by streets or other features on all sides * Blocks can be discontiguous and split by other blocks or streets * The City is broken up into over 6,000 blocks and over 200,000 individual lots > **Note:** You will see reference to `mapblklot` in some City data. This is to reference a 1:M relationship of vertical parcels to a base parcel; e.g. condo or timeshare lots. > > The practice of representing a vertical lot digitally is to duplicate and "stack" the base parcel for each vertical lot in the building, assigning each a unique `blklot` number. The `mapblklot` is the reference to the base APN. So `blklot` will be unique, while `mapblklot` will duplicate across vertical lots. ### Illustration ![Image illustrating the relationship of lots to blocks](/files/dFRsXbm2tjnsCCFL279p) * Block 0117 above is bounded: * On the North and South by Union and Green Streets * On the East and West by Stockton and Powell Streets * Columbus Avenue bisects it, but both sides are still part of the same block * The block is subdivided into lots numbered from 001 through 021 * A full Assessor Parcel Number would be the concatenation of the block and lot * Blocks are 4 digits with an optional letter suffix - 117 becomes 0117 * Lots are 3 digits with an optional letter suffix - 4 becomes 004 * The full APN for lot 4 in block 117 is [0117004](http://propertymap.sfplanning.org/?search=0117004) * These are [recorded in paper maps](http://sfplanninggis.org/BlockBooks/AssessorBlock0117.pdf) in the Office of the Assessor Recorder and digitized ### Authority * Recordation of final parcel maps happens with the Office of the Assessor-Recorder * Before recordation, subdivision maps are approved by the County Surveyor, the Public Works Director and the Board of Supervisors * More information about the [subdivision process and related codes on the Public Works website](http://sfpublicworks.org/services/subdivisions-and-mapping) ## Use * Assessor Parcel Numbers are used to tie deeds and legal records to property * Assessor Parcel Numbers used to assess and collect taxes on land and improvements * As a common administrative identifier for a number of processes like permitting ### Accepted values * Must be provided in a dataset as 2 separate fields: * Block as `blk` or `block` or `block_num` - must have 4 numeric digits and an optional letter suffix * Lot as `lot` or `lot_num` - must have 3 numeric digits and an optional letter suffix * When representing the fully qualified APN as a single field: * Name the column either `apn` or `assessor_parcel_number` or `blklot` or `block_and_lot` * Concatenate the block and lot values together * Do not separate the block and lot number with space or other characters * 0585012D instead of 0585/012D * Do not prepend with additional text like `APN` or `Block and Lot Number` * Current parcels and corresponding identifiers in the current subdivision parcels below * Historic parcels and corresponding identifiers in the recorded parcel geography below (note limitations) ### Reference Datasets | Dataset | Description and Constraints | Block Column | Lot Column | APN Column | | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------ | ---------- | ---------- | | [Current Subdivision Parcels](https://data.sfgov.org/Geographic-Locations-and-Boundaries/Subdivision-Parcels-aka-City-Lots-/45et-ht7c) | These are the current active recorded parcels. The geography can be used as reference but should not be used for anything requiring precision. | `block_num` | `lot_num` | `blklot` | | [Recorded Parcel Geography with Transaction Date History](https://data.sfgov.org/dataset/Recorded-Parcel-Geography-with-Transaction-Date-Hi/25dk-perw/data) | These are the current and historic parcels with recorded dates. Historic parcels only go back to about 1995 with some exceptions. Useful for tying historic administrative records to a location. The geography can be used as reference but should not be used for anything requiring precision. | `block_num` | `lot_num` | `blklot` | | [San Francisco Assessor Blocks](https://data.sfgov.org/Geographic-Locations-and-Boundaries/San-Francisco-Assessor-Blocks/ndp2-nsue) | Just the blocks without lots | `block_num` | N/A | N/A | ### Is anything wrong, unclear, missing? [Leave a comment.](https://github.com/DataSF/draft-publishing-standards/issues/new?title=Comment:Parcels\&body=Comment:Parcels)