Skip to main content
Lake County, Ohio - Engineer

Survey Data

    Links for Survey Data Including Road Records and GPS Data

    Existing Lake County GPS monument coordinates are based on NAD 83 (1986 adjustment), Ohio State Plane North 3401.  The vertical positions were adjusted using NAVD 88, Geoid model 1999.  Most of the original “blue booked” monuments were set in 1991.  Many have been destroyed even though NGS still have the positions listed.

     Since 2003 we have added to the densification of GPS monuments by using Trimble equipment in the field and office.  Lake County GPS positions are still NAD 83, OSP North 3401, (86 adjustment) but the vertical postions are now NAVD 88, GEIOD Model 2003.  Whereas NAVD 88 has remained the same please note the geoids model change.

     Be aware that Lake County’s base station, “OHLA” is now part of NGS CORS and ODOT’s VRS (Virtual Reference Station).  OHLA’s position was adjusted by NGS using NAD 83 (2007) Re-Adjustment, Navd88, Geiod 2003.  Ohio’s HARN monuments are also part of this 2007 re-adjustment and therefore any HARN monument or CORS held will cause a difference in the Lake County GPS monuments, specifically in the Northing. The vertical results will be within instrument specifications and will be difficult to distinguish error.  Please remember, Lake County’s GPS data and GIS are on NAD 83 (1986 Adjustment), Ohio North 3401, State Plane Coordinates, NAVD 88.

     To access information at the NGS Website for OHLA CORS:

     CLICK HERE and enter Site ID "OHLA"

     Links ARE CONTINUOUSLY UPDATED so check back for new information.  For all questions or comments please contact the survey department at the Lake County Engineer's Office (440.350.2770).

     Survey Department:     

         -  George J. Hadden, PE, PS, Chief Surveyor

         -  Wesley M. Edwards, Survey Technician II

         -  Michael L. West, Survey Technician II