Central Oregon Coordinate System

CENTRAL OREGON COORDINATE SYSTEM (COCS, aka COGRID)

Background information: 

The Central Oregon Coordinate System (COCS) was developed by W.C. Kauffman, PLS, to whom we are grateful. The control network was started in June of 1988 by the Deschutes County Public Works Department for the evaluation of G.P.S. survey for the control of a county wide G.I.S. project. The Public Works Department turned the project over to the Deschutes County Surveyor’s Office in July of 1991 for the completion of additional field work and analysis/adjustment.

The County Surveyor’s Office and the County GIS Section agreed on a conformal mapping projection for the best fit of the 80% population area of Deschutes County, for grid to ground distances being no worse than 1:50,000. The COCS is a low distortion projection which has been adopted and used by many local surveyors over the intervening years. The COCS is defined as follows: 

Linear unit: International foot (ift) 
Geodetic datum: North American Datum of 1983 (1991) 
Vertical datum: National Geodetic Vertical Datum of 1929 (NGVD29) 
System: Central Oregon Coordinate System 
Projection: Transverse Mercator 
Latitude of grid origin: 43° 00' 00" N 
Longitude of central meridian: 121° 17' 00"W 
Northing at grid origin: 0.000 ift 
Easting at central meridian: 3,300,000.000 ift 
Scale factor on central meridian: 1.00016 (exact)