Cadastral Maps and County Grid Numbers

The County Cadastral maps will be on the County Surveyor's Website this month, probably about mid-month if all goes well.  These are digital files that you can open and save for your use.  The information on these maps were last updated about 1986-88.  At that time the County Surveyor's mapping program was discontinued by the County and the maps were left untouched.  So these are the mylar maps that were scanned into TIFF and PDF files.  The maps were on 26" x 36" mylars, made from the historical process of using overlays, Leroy lettering and hand drafted with inking pens such as  Rotring and by Koh-i-Noor. (historical drafting that predated CAD)  They are useful for determining the County Grid Number which is used for geographically indexing maps.  Our Planning and Land Development-Engineering (LDE) uses the County Grid Number in their files also.  So this is useful in doing research.

Here's some general information.

County Cadastral Map

Generally, cadastral maps are use to portray boundaries of tracts and subdivisions of lands within the County of Santa Clara.

A cadastral map is a map showing the boundaries of subdivisions of land.  It is based on bearings, lengths and areas of individual tracts, for purposes of describing and recording ownership.  Some areas on the cadastral map may also show topography, drainage, and other features relating to the value of the land and its uses.  The cadastral map number is the first number used in the series of three numbers for determining the County Grid Number.  For example: County Grid No. 67-37-70 where 67 is the Cadastral Map number.  See below for the rest of the County Grid Number. 

The Cadastral Map layer is comprised of the County Cadastral Maps series that cover the entire County of Santa Clara.  It contains 281 individual maps and numbered from west to east and from north to south.  Cadastral Map No. 1 is in the northwest area of Santa Clara County.

Each cadastral map covers approximately 150,000,000 ft sq..

County Grid Number (XY Grid Index)

Sometimes referred to as the xy grid, grid index, Santa Clara County Grid, County Grid Number.

Santa Clara County Coordinate System is a grid system comprised of x coordinates that run west to east and y coordinates that run south to north numerically. 

Each County Cadastral map has a grid as follows:

6 grids east and west (X-axis) that covers approximately 15,000 feet 

4 grids north and south (Y-axis) that covers approximately 10,000 feet 

They are based on California Coordinate System (CCS) but I'll go into that on another Blog....

Here's a sample of a Cadastral Map No. 67
From the example above, for our office which is located in County Grid No. 67-37-70 means Cadastral map number, 37 is the x-value and 70 is the y-value.