The mapping project helped the Client solve lots of important issues and the TopoDrone-100 accuracy proved to be paramount in this respect. The Client is licensed by the Environment Protection Authority (EPA) to build the waste mounds to an absolute height of 26m above sea level (ASL). After several months, the compaction of the waste, due to it’s own weight and top-soil, reduced the height of these large waste mounds. This provided the opportunity for more waste to be added onto the same mound. Therefore, it became vitally important that the accurate height of the mounds is regularly monitored as this would ensure that the mounds are always under the absolute ASL height, which is a legal obligation. At the same time, monitoring the amount of waste mound compaction allowed the Client to financially benefit by adding additional waste to the same mound.
Secondly, the project also involved the mapping of the whole area owned by the Client, in order to be used as the base mapping for future planned expansion of the waste processing requirements. Importantly, the mapping needed to be accurate to compare Ownership with Occupation (cadastral boundary which is ownership versus the fencing on the presumed boundary which is occupation).
A high accurate photogrammetric mapping system TopoDrone-100 reliably mapped a waste recycling site covering the area of 4sq.km and captured 2,5cm GSD aerial imagery with 25mm absolute accuracy. The company specialists launched and landed from open paddocks, and the whole flight sortie took 60 min of flight. They measured by kinematic GPS survey 10 detailed features to use as the GCP’s for the photogrammetric processing. The data processing took 2 hours.
Tom Tadrowski, Executive Director of DroneMetrex, says: “Because the TopoDrone-100 uses our unique (patent-pending) Gyro-stabilised Active Mount (DMX-GAM), which houses a 24Mp digital camera with Zeiss lens, full-framed sensor and leaf-shutter, the imagery captured is “photogrammetry-ready”. To explain; each image is near-nadir, no crab, and without the random geometric errors of all other digital camera systems. We then process with our own software in the pre-processing stage correcting for the known systematic errors. Once we have the photogrammetric aerial triangulation, and then the generation of the dense point-cloud, we treat this as our base product which allows us to further generate the DTM, DSM, digital orthophoto mosaic, contours and profiles. Because our TopoDrone data is proper photogrammetric data, we are able to use the stereo image pairs for accurate human “heads-up” 3D digitising of line features if required. The unique mapping accuracies of the TopoDrone enable us to confidently provide photogrammetric accurate data.”
DroneMetrex Pty Ltd is a company specialising in the autonomous data acquisition, near real-time data feeds, and accurate survey and photogrammetric mapping information services from “Drones”. This provides alternative solutions to costly data acquired from aircraft or similar airborne and/or vehicular platforms over areas that are not economically justified to be captured by such large aircraft, or may be difficult and/or dangerous for “manned” aircrafts or vehicles or ground survey teams. With the TopoDrones the company produces truly accurate mapping data – 25mm accuracy in height – reliably, repeatedly, accurately.