1121 Boyce Road
Suite 3100
Pittsburgh, PA 15241
Tel: 724-942-2881
Fax: 724-942-2885
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Keddal has been performing ground-based photogrammetric control and other types of ground surveying work for over 40 years and currently has multiple field crews operating from its headquarters and other branch production offices. All ground-based survey work is overseen by a licensed professional land surveyors and experienced geodesists. Keddal surveyors have worked in over 40 different US states and territories and in a number of foreign countries on four continents.
Keddal's ground-based surveying is primarily accomplished with Trimble geodetic-grade (centimeter accuracy) GPS receivers operated in static or kinematic mode, depending on the project requirements. Trimble mapping-grade receivers are used for sub-meter accuracy survey work. Other ground survey instrumentation Keddal owns and regularly operates includes Leica automatic levels, TOPCON total stations, and Wild theodolites.
Keddal's ground-based control survey experience includes establishment of thousands of permanent monuments (e.g., NGS Class "C" concrete) and tens of thousands of semi-permanent (e.g., capped iron pins) and photo-identifiable (e.g., sidewalk corner intersection) control points.
The permanent monumentation work has included over 20 NGS "bluebook" surveys. Horizontal control is typically surveyed to 1st or 2nd order accuracy via GPS while vertical control is surveyed to 3rd orderr accuracy with GPS or 2nd order accuracy with precise leveling. Survey datums typically used include NAD83 and 27 state plane horizontal, NAVD88 and NGVD29 vertical, UTM, and local or arbitrary geodetic datums. Keddal survey crews are responsible for preparing detailed field sketches/recovery records of all control point locations and for placing, monitoring, and removing appropriate targets for monumented control locations.
Before commencing the control survey field work, a project control network plan is developed and reviewed with the client. The control plan accounts for the project mapping and accuracy requirements, locations/availability of access corridors and existing control, flight pattern, use of airborne GPS, and other relevant factors, with the general objective of providing georeferencing checks and preventing extrapolation throughout the project area.
The control network plan is adjusted as needed for actual field conditions, with the final plan being included along with final control listings, observation records, control station sketches, and adjustment output data in a comprehensive survey report provided to the client at the completion of the survey.
In addition to geodetic and photogrammetric control surveys, Keddal's survey crews have significant experience performing field verification, utility, boundary, hydrographic, obstruction height, topographic, earthwork/volumetric, deformation/subsidence, wetland, and other types of ground survey work. The ground surveys have covered a variety of specialized sites, including highways, railroads, dams, lakes and rivers, airports, transmission lines, plant sites, landfills, hazardous waste sites, and wetlands. The survey crews operate under general company and project-specific safety plans and have undergone extensive safety training.
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