Landbase Information Systems

The G.L.I.S Landbase Information Systems Section is where the County of Orange Landbase is generated and updated. This unit prepares and maintains an information system consisting of a very accurate, parcel-level digital basemap containing over 665,000 parcels.

The Landbase contains street centerlines, right-of-way lines, and parcel boundaries, linked to text information, such as assessor parcel number. The foundation of this system is the County Control Network consisting of over 2400 control points on an approximate half-mile grid. This strong foundation makes the County Landbase very accurate and allows new map information to be added without losing any accuracy.

The following questions are Frequently Asked Questions. If you have questions that are not covered in this list provided, please feel free to contact us. Please take the time to provide us your information and the questions that you may have clearly.

OC Survey’s Land Information Section maintains the OC Landbase, which is a digital basemap of Orange County containing legal parcels, districts, and transportation layers. See Data Dictionary pdf for a listing of OC Landbase content. The OC Landbase is based on information from recorded legal documents and is primarily intended to reflect lines of ownership (“cadastre”) rather than assessor parcels. Please contact the Orange County Assessor for attribute information they collect.

To assist The County of Orange in the maintenance and/or correction of the data, users should provide the County of Orange with information concerning errors or discrepancies found in using the data. Please acknowledge the County of Orange as the source when data is used in the preparation of reports, papers, publications, maps, or other products.

The coordinate system for the OC Landbase is NAD 83, CA State Plane Zone VI, OCS 2007.00 adjustment; units are in US Survey feet.


The OC Landbase can be delivered over the Internet through our data portal, which allows content to be downloaded in a variety of formats including ShapeFile, MapInfo and KML. This portal improves access to users who don’t have the necessary software to view the data. Alternatively, the OC Landbase can be delivered by mail on CD/DVD disc in Oracle’s dump format for $10.

See for Internet or mail delivery instructions.

Additional Information:

Frequently Asked Questions can be found here. If you have questions that are not covered in this list provided, please feel free to contact us.