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Topographic Surveys & Digital Orthophotos Background SMC has successfully completed a considerable number of topographic surveying projects ranging in size and complexity from small sites to town wide projects. In keeping with the company’s underlying philosophy, “the key to accurate surveying and mapping still lies in the skillful use of the right instruments and techniques guided by seasoned judgment”, SMC’s Project Director will meet with prospective clients to discuss the proposed project in detail to determine the requirements necessary to meet the accuracy standards for the project. In general, these accuracy requirements determine the scale and contour interval for the topographic survey. When feasible, SMC will use a municipality’s G.I.S. basemap. If the accuracy of the existing basemap cannot support the design requirements for a particular project, SMC’s technical staff will employ its collective experience, skill and seasoned judgment to develop the appropriate surveying and mapping techniques to be used for the project. Turnkey aerial survey services are provided and supplemented with field surveys to capture data relevant to the design of a particular project.
Technology/Methodology In general, low-level color aerial photography is used to generate the basemap. The flying height selected is chosen after particular attention is given to the contour interval required for the project. When the decision is made to utilize project specific aerial photography, SMC’s technical staff plans the flight lines and develops the ground control configuration. The location of existing federal or state geodetic control monuments are researched and targeted if appropriately positioned within the footprint of the aerial photography. Suitable survey monuments are installed and targeted and their respective positions established using GPS surveying techniques. Additional control is established using the more conventional “total station" distance and angular measuring instruments and a combined adjustment of the satellite and terrestrial measurement data is undertaken. Similarly, when existing basemaps are to be used for a project, SMC’s technical staff will develop a project-wide horizontal and vertical control network referenced to the coordinate system used for the development of the basemap. Supplemental field surveys will be referenced to this project-wide control network. Orthophoto - Municipal Mapping Project Topography - Municipal Mapping Project
Supplemental Field Surveys
For some projects, it may be appropriate to conduct field surveys to locate the required data. For these occasions, SMC’s staff will utilize “total station" instruments to locate buildings, edges of pavement, walks, walls, fences and other details in addition to the location of surface evidence of utilities, determination of sill elevations of houses when required and the location of wetland flags. Depending on the project requirements, additional field surveys can be undertaken to locate details that are not visible on the photography but are required by the project design team. Typically, a field edit walk-through will be conducted to identify pavement, curb, wall, building and fence types. Final plans are typically delivered in AutoCAD® format.
Value Added Services There are a number of value added services that SMC can provide to extend the value of the topographic survey. As an example, SMC can provide a comprehensive utility inventory involving record research and field surveys to locate utility markings. Additionally, we can provide Digital Terrain Models (DTM) and digital orthophotos.
Following the preliminary design effort, SMC’s staff provides value added services with the preparation of easement and/or taking plans. This task involves research to obtain appropriate data (deeds, recorded plans and street layouts) relative to the location of property lines and field surveys to locate property monuments that may not have been located during the supplemental field surveys. SMC’s staff prepares easement and/or taking plans along with descriptions of the affected properties. The plans are suitable for recording at the Registry of Deeds in Massachusetts or appropriate county or municipal facilities in other states. A further value added service, provided by SMC, is the staking of easements and/or property lines during the construction phase of a project.
Following is list of projects that SMC’s staff has successfully completed:
Key Benefits
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ndaly@smcsurvey.com
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