City Lots

Metadata also available as

Frequently-anticipated questions:


What does this data set describe?

Title: City Lots
Abstract:
The CityLots spatial data layer is a representation of the City and County of San Francisco's Subdivision parcels. Each of the 193,000-plus polygons has a unique BLKLOT identifier which is the Assessor Parcel Number (APN). Multiple level (condominium, live/work, et al.) lots are represented as well, with their ground or base lot being the MAPBLKLOT key.
Supplemental_Information: LAST UPDATE: 2 MARCH 2006
  1. How should this data set be cited?

    City and County of San Francisc, Department of Public Works, Bureau of Stre, March 2, 2006, City Lots.

    Online Links:

    • Server=tisent20; Service=port:5151; User=sfgis; Version=SDE.DEFAULT

    Other_Citation_Details:
    Updates made on bi-weekly basis, then published to SFGIS Library.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.516073
    East_Bounding_Coordinate: -122.355861
    North_Bounding_Coordinate: 37.833511
    South_Bounding_Coordinate: 37.706018

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 02-Mar-2006
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • G-polygon (193596)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 37.066667
      Standard_Parallel: 38.433333
      Longitude_of_Central_Meridian: -120.500000
      Latitude_of_Projection_Origin: 36.500000
      False_Easting: 6561666.666667
      False_Northing: 1640416.666667

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000115
      Ordinates (y-coordinates) are specified to the nearest 0.000115
      Planar coordinates are specified in survey feet

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 1.000000
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    SDE.SFGIS.CITYLOTS

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    MAPBLKLOT
    Concantenated Block and Lot Number. (Source: CCSF)

    Coordinates defining the features.

    BLKLOT
    Concantenated Block and Lot Number of the base lot for this polygon. (Source: CCSF)

    BLOCK_NUM
    Lot Number. (Source: CCSF)

    LOT_NUM
    Block number of the lot. (Source: CCSF)

    FROM_ST
    In the address range for the lot, the "from" address number. (Source: CCSF)

    TO_ST
    In the address range for the lot, the "to" address number. (Source: CCSF)

    STREET
    The address street for the base lot. (Source: CCSF)

    ST_TYPE
    The type of street for the base lot. (Source: CCSF)

    ODD_EVEN
    Indicates if address number is odd or even. (Source: CCSF)

    ValueDefinition
    OOdd
    EEven

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    SHAPE..Area()
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    SHAPE..Length()
    Feature geometry. (Source: ESRI)


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    City and County of San Francisco Department of Public Works/Bureau of Street-Use and Mapping

  3. To whom should users address questions about the data?

    City & County of San Francisco
    875 Stevenson St
    San Francisco, California 94103
    USA

    415-554-0800 (voice)
    415-554-0886 (FAX)
    gis@sfgov.org

    Hours_of_Service: 9am-5pm, Monday-Friday


Why was the data set created?

The CityLots layer is one of the principal datasets which comprise the City's Basemap. The layer serves as the foundation for map display and analyses, and can be joined to any City dataset which has block and lot information in the proper format.


How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    (process 1 of 1)
    The Department of Public Works/Bureau of Street-Use and Mapping (DPW/BSM) is the City agency is responsible for processes related to Subdivision Map Act. These include processing requests for new condominiums, condominium conversions, lot line adjustments, lot mergers, lot splits and other requests which result in new Basemap transactions. Once a Subdivision project has been recorded with the Recorder's Office, a new transaction is generated for the DPW/BSM Basemap Operator. The Operator will make the appropriate changes in one of the 74 AutoCAD drawings which represent the Subdivision parcels. When the change is commited to the database, the new lots are are added as spatially-enabled records to the ArcSDE geodatabase, and the old lots are "dropped" from the database (actually, tagged as no longer current, and thus are removed from the active lots layer).

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    Global Positioning System (GPS) Control Survey: a GPS survey of 65 survey control points was conducted, generating coordinate and elevation data for the survey point network used for Basemap development. The network meets the National Geodetic Survey standard for Second Order, Class 2. Orthophoto accuracy: Ninety percent of points on an orthophoto are ± 2.5 feet of survey point coordinates for the same point. Planimetric features (citylots, sfblocks, cityfeatures, street centerline files) are overlaid on the orthophoto images with an accuracy of ± 2 foot.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

  5. How consistent are the relationships among the observations, including topology?


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: Currently must be city employee, city contractor, or licenseee.
Use_Constraints:
Only a representation of the lot boundaries, for legal matters please consult the Recorded Parcel Maps, Deeds, and Assessor Block Maps directly.

  1. Who distributes the data set?[Distributor contact information not provided.]

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 03-Mar-2006
Metadata author:
City and County of San Francisco
875 Stevenson St
San Francisco, California 94103

415-554-0800 (voice)
415-554-0886 (FAX)
gis@sfgov.org

Hours_of_Service: 9am-5pm
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.8.6 on Wed May 03 10:15:39 2006