Map Associates Inc. (DBA) NorthStar Engineering was retained to develop, prepare and process a multiple Phase Tentative Subdivision Map and after approval to prepare the phased improvement plans and boundary. The real property involved has an area of approximately 333 acres with an ultimate build out of approximately 300 Lots along with numerous open space parcels and wetland reservation areas. Part of the initial effort was the location and setting of aerial targets, the search and recovery of monuments and the establishment of the exterior boundary of the parcel. This project involved the use of conventional surveying equipment, RTK and Static GPS land surveying equipment and photogrammetry to accomplish the project objectives.
NorthStar Engineering’s responsibilities and methodology included the following:
- The completion of a horizontal and vertical control survey.
- This control survey was accomplished using a combination of RTK and static GPS observations and differential leveling. GPS observations were completed multiple times with different satellite configurations to give redundancy in the measurements. These observations were used to establish the horizontal positions of the control points and the differential levels were held for the vertical positions. The Static observations were then used to complete a NGS Online Positioning User Service (“OPUS”) position in NAD 83 California Zone II State Plane Coordinates with an EPOCH of 2002.0000.
- This control was then used to determine the location of aerial targets to control detailed aerial photography for 1″ = 20 foot scale maps with one-foot contours, and color digital orthophotos with a 0.2′ pixel resolution. A digital terrain model was created from the one-foot contours and spot elevations. The actual photogrammetric work was completed by others.
- The boundary determination involved sectionalized land procedures along with metes and bounds deed interpretation. There was extensive monument search and recovery completed to assist in this determination. This recovery effort involved both conventional and GPS survey techniques.
- Maps were prepared in an AutoCAD format to show the results of this boundary work. A Record of Survey map was filed on the boundary.
- The topographic mapping created from the photogrammetric work was supplemented with conventional topographic work where necessary.
Total contract costs to date are $200,000.00. Of that total costs $52,000.00 was for the control, boundary and topographic work described above. This cost figure does not include the actual photogrammetric work by others.
Record of Survey Map