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Height Modernization / Digital Leveling - Oahu and Maui, Hawaii


The National Geodetic Survey website defines the important work of Geodetic Leveling as "...the process of determining elevations above mean sea-level. In geodetic surveys executed primarily for mapping, geodetic positions are referred to an ellipsoid, and the elevations of the positions are referred to the geoid. However, for satellite geodesy the geoidal heights must be considered to establish the correct height above the geoid. Precise geodetic leveling is used to establish a basic network of vertical control points. From these, the height of other positions in the survey can be determined by supplementary methods."

Custom discs were produced to comply with NGS standards.

Sam O. Hirota, Inc. (SOH) was selected by the Hawaii State Department of Transportation to conduct Digital Leveling along approximately 400 miles of roads on Oahu, Maui, and Kauai. SOH worked closely with HDOT so that submitted project safety plan, quality control plan, and survey plan could be reviewed and approved in a timely manner.  On Oahu, SOH completed recovery of existing survey control stations, had project plans approved, set new control stations, and completed digital leveling in the allotted time.  


In an evaluation completed by State of Hawaii DOT, SOH was rated as Excellent for all factors. The evaluation cited communications responsiveness, cooperation with HDOT personnel, completeness of Survey, Quality Control, and Accident Prevention plans, and an "...excellent grasp of the complexity of the digital leveling and the NGS manual that explains all the field and office procedures used daily." 


On Kauai, training, project planning, and station recovery have been completed and digital leveling has begun.  SOH expects completion of the project ahead of schedule.

Services Provided:

  • Land Surveying/Digital Leveling

  • Attended training sessions run by State DOT and NGS

  • Contributed to development of new NGS procedures using new digital levels

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