Flatirons, Inc.
- Surveying, Engineering & Geomatics
A Full Service Land Surveying Company Serving Boulder County And The Colorado Front Range
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Aerial MappingAerial mapping can be used to map the horizontal and vertical features of large areas of land in a more efficient manner than is available by traditional survey methods. A series of aerial photographs are used to create a stereoscopic image of the ground. Each photo must have several points of known XYZ coordinates identifiable in the photo. These known points are used as the basis to create an accurate photographic model or digital terrain model of the subject area, after which accurate horizontal and vertical information can be obtained from the photos. The advantages of aerial mapping are realized in several ways on larger sites, especially by increased efficiency over traditional survey methods in gathering large amounts of information. Possible drawbacks are features obscured by foilage or unidentifiable from aerial photos, and the possibility of less precise (though not necessarily less accurate) information than that obtained by traditional survey methods.
Flatirons, Inc.'s use of a combination of GPS for horizontal control and traditional methods for vertical control allows us to provide the accurate information needed to bring an aerial mapping project to a successful conclusion. Aerial Photography and Remote Sensing, The Geographer's Craft, University of Colorado at BoulderNational Map Accuracy Standards from the U.S Geological SurveyPhotogrammetry—NOT! from Professional Surveyor magazine archivesPhotogrammetry: A Revolution in Technology from Professional Surveyor magazine archives |
The surveyor's role in aerial mapping is usually two-fold; to provide horizontal and vertical control for the mapping, and to provide supplemental information for the aerial mapping. The surveyor, under the direction of the aerial mapper, places aerial targets on the ground at positions that will provide adequate visual coverage for the photography. The surveyor will then provide the mapper with a list of coordinates and elevations for each aerial target, which are then used as control to set up the photographic model of the site. Supplemental information provided by the surveyor can include manholes, fire hydrants, or other items not visible by photo. In areas of critical match points, the surveyor may be able to provide information that is more precise than available by aerial mapping.