City Spheres of Influence

The sphere of influence dataset represents the nine cities, urban (incorporated) municipality sphere of influence (e.g. SOI) boundaries within the County of Sonoma as determined by the Local Agency Formation Commission (LAFCO).  See Data Quality - Attribute Accuracy tab for boundary modification history.

A "sphere of influence" is a physical boundary a local governmental agency is expected to provide services for and is generally set by Sonoma LAFCO with a 20-year time frame.  Sphere of influence boundaries are designated in order to help discourage urban sprawl, limit boundary disputes between local agencies, and provides indications regarding future development potential.  A district or City's SOI should not to be construed as "referral" areas or as bestowing authority and control in the sphere area.  LAFCO can amend a SOI if there are sound reasons to do so.

Since the GIS data was developed for planning purposes and use in publication of maps and/or database creation, the data is for illustrative purpose only and is not suitable for parcel specific decision making. 

Therefore, the GIS data presented herein are approximations and further land development determination is at the discretion of the PRMD planning staff which may require a parcel specific site review (to draw parcel specific conclusions).

Creation methodology & resources:
1) refer to Data Quality - Attribute Accuracy tab for historical dataset modifications by ActiveMap version release number
2) when incorporated (e.g. City) spheres of influence are modified and recorded with the County's Recorder, boundary data is modified to reflect current city boundary data - this dataset takes into account ALL RECORDED SOI documentation as of 08/18/08
3) for ActiveMap Data Capture December 2010 [ver. 2.1], rectified dataset to AM_PARCEL 10/22/2010 (validated topology; no edits needed to rectify dataset to new parcels)

Note:
On October 13, 2003, PRMD received LAFCO's approval on accuracy of shapefile data.  The boundaries are maintained through the active participation between PRMD-GIS, LAFCO (Local Agency Formation Commission), Assessor's Office and staff (i.e. planners, GIS analyst) of the respective City's.

Non-contiguous annexations/parcel(s) are NOT shown as part of the City's SOI boundary.  This is due to the fact that the use of the parcel(s) fail to meet the 4 SOI determining criteria for being included within the SOI boundary.  The criteria factors are solely based on the utilization of the parcel(s) for the "potential of growth" and the parcel(s) being utilized for municipal purposes fails to meet the criteria for growth.