.

GeoInformatics-7-2009
article craft was equipped with a trimble geoxt handheld computer with integrated global positioning system (gps) capabilities and a nikon d70 camera. the combination of these two systems turns the nikon into a gps camera, collecting an aerial image and a gps location and linking the photograph to that gps location. flight protocols were designed and implemented to maximize water penetration and aquatechnex collected a seamless stream of images with a 30 percent overlap that covered the entire area of interest. the aquatechnex team opted to use trimble equipment because of their familiarity with the geoxt handhelds, which they use for several client weed management projects, as well as its ruggedness and all-day battery life. the team was able to capture the precise flight line of the aircraft by automatically logging gps data points every five seconds using trimble terrasync data collection software. geospatial expert s gps-photo link software latest news? visit www.geoinformatics.com then linked these gps data points with the nearly 400 aerial photos collected during the flyover and dropped them into the arcgis project file exactly where they were collected along the flight line. these images are then available in arcgis as a hot link and can be viewed by clicking on an image point of the planes flight line. aquatechnex also used trimble gps pathfinder office software to process the differential gps corrections and to export the data to esri arcpad gis software for use of the resulting basemap in the field. this data gave the field team a more complete picture of the lake area and a comprehensive understanding of the location of the noxious weed. this innovative aerial mapping approach allowed the aquatechnex team to survey, analyze, and report on nearly 100 miles (161 kilometers) of shoreline in onlyfive days, saving the county tens of thousands of dollars over conventional mapping techniques. anytime you re faced with a weed management issue and you re working on the water there are no reference points, said terry mcnabb, an aquatic biologist and owner of aquatechnex. that s why we had to develop an aerial shoreline analysis model using remote sensing, gps, and gis mapping technologies from trimble and esri. it s really a highly accurate and cost-effective way to map a sizeable weed infestation like this, said mcnabb. with the geoxt handhelds, together with digital imagery, we were able to complete a very accurate survey for approximately $6,000, in contrast to conventional aerial mapping and field methods which would have cost up to $60,000. through this extensive yet efficient mapping process, aquatechnex determined that approximately 4,000 acres (1,618 hectares) of the lake pend oreille system was infested with eurasian milfoil, and was able to identify more than 100 specific locations of infestation from analyzing the aerial photos. the next step in the project was to validate october/november 2009 17
Powered by fluidbook tm