What coordinate system does Napa County use?
Napa County has standardized on California State Plane Coordinates, Zone II, NAD83. All units are measured in feet. A standard for vertical measurements has not been adopted at this time. 2) Who can get copies of the data? Please refer to the Data Distribution Policy & Fees page for complete details about accessing our data. 3) Why doesn’t the data line up? The data in the GIS system comes from many different sources. Each of the layers was processed by different individuals using a variety of methods and original sources. The result is that sometimes the layers do not line up well with each other. For example, the road network does not always match the right-of-ways in the parcel database. Currently, the Public Land Survey System (Township & Range) and the 1993 DOQQs serve as our base map. Where possible, other layers have been adjusted to this base. In some cases, however, it is not possible or feasible to adjust individual layers. 4) How was the Parcel layer created? The Parcel laye
