News & Information

Address Point Layer Data Quality Improving

SanGIS to Publish New and Expanded Address Point Layer

SanGIS is continuing its efforts to improve the address point layer data quality and usability. In December, SanGIS purchased commercial address verification software in order to examine the consistency of the address points and to identify corrections that need to be made. That project is still in progress and the data is being updated on an ongoing basis.

At the SanGIS Technical Advisory Board (STAB) meeting in December, we presented a number of proposals for alterations to the published address point layer that we felt would make the data more usable, create better geocoding results, and provide better information for our users. Not all recommended changes were approved but many were. Effective with the monthly data updates the first week in March you will see the following changes in the address point layer:

  1. In the past all address points were published at the centroid of the parcel they are associated with. In the new address point layer all addresses maintained by SanGIS (ASOURCE=S) will be published at the actual placement location. This will allow SanGIS to start publishing addresses on the actual structure or property entrance point. All addresses derived from the Assessor Master Property Record (ASOURCE=M) will continue to be published at the parcel centroid.

  2. We will add an attribute to indicate the address location. The following domain will be used:

    S Structure Assumed main entrance of primary structure on parcel
    E Entrance Driveway or other primary access entrance at parcel boundary
    C Centroid Centroid of the parcel polygon (as adjusted on an annual basis)
    U Unknown Placement location is not one of the items above
    R Review Point location has not been determined and requires review to determine

    In the initial publication all SanGIS maintained points (ASOURCE=S) will be coded “R” and all MPR points (ASOURCE=M) will be coded “C”. SanGIS editing staff will begin reviewing all SanGIS address points and adjusting the placement location as needed. At that time the placement attribute will be changed to indicate the location. This review will take several months to complete. The preferred placement location will be on the primary structure (code=S).

    MPR points will always be placed at the parcel centroid and will always be coded “C”.

  3. In the current address point layer, zip codes are published only for the SanGIS maintained points. In the new publication, a zip code will be published for all addresses. For SanGIS maintained addresses the zip code will be derived from an overlay with the SanGIS zip code layer. For Assessor maintained points the zip code will be the value in the MPR.

  4. A Postal Community attribute will now be published with each address. The Postal Community will be the name assigned to the zip code by the US Postal Service. For SanGIS addresses this will be derived from the zip code layer. For Assessor maintained addresses the Postal Community will be the name in the MPR. Note that the jurisdiction code will continue to be published as part of the address point record.

  5. SanGIS will add a state code (CA) to all address point records. This should facilitate geocoding and mailing label creation.

  6. SanGIS address points include an Address Type attribute that is currently not published. This attribute indicates whether the address is something other than a structure (such as a valve or light pole). SanGIS will begin publishing this value, along with the domain descriptions, to provide more information on the particular address point. Note that this value will apply only to SanGIS maintained address points (ASOURCE=S). Assessor maintained addresses will not include a value in this field.

  7. The US National Grid (USNG) value will be calculated for the placement location of each address point and published as an attribute. The USNG value will be determined to the nearest meter (e.g. 11S NS 06713 25915). The California State Plane Coordinates (X,Y) of the parcel centroid will continue to be published as attributes. For more information on the US National Grid visit:

We hope that these changes will make the address point layer much more useful in your projects and processes. If you have additional recommendations please send us a note. Note that one thing we are working on, but will not be including in this initial update, is to add a unique address identifier for each point. Due to the nature of our address publication process and the multiple address sources we use, this is a more difficult change to implement.

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