Digital Elevation Models

Mapping terrain by ground survey is slow, costly and sometimes unsafe in steep, remote or hazardous areas such as open-pit mines, mountain exploration leases and active volcanoes. Geoimage, an Australian satellite imagery and geospatial company, produces Digital Elevation Models from satellite imagery, processed in-house to each client's specification: Digital Surface Models (DSMs) that include buildings and vegetation, and Digital Terrain Models (DTMs) of the bare ground.

Custom DEMs are generated from stereo or tri-stereo acquisitions, archive or fresh capture. Geoimage's DEM guide lists Pléiades, SPOT 6/7, WorldView-1 to -3 and GeoEye-1 as source sensors, with resolutions from 0.5 m to 20 m. Tri-stereo adds a near-nadir view to the forward and backward images, reducing occlusions in pits, caldera walls and steep slopes. As off-the-shelf alternatives with shorter turnaround, Geoimage supplies AW3D, built from the ALOS PRISM archive (Geoimage is a licensed AW3D reseller for the Asia Pacific region), and Airbus WorldDEM Neo, a 5 m global elevation model.

Stated uses include contour generation, flood and watershed modelling, engineering and infrastructure design, image orthorectification, slope analysis for bushfire risk and mobile network analysis. Published projects include 5 m AW3D for First Quantum Minerals' exploration in the Peruvian Andes, an AW3D Level 2 DSM and contours along Queensland Department of Transport and Main Roads corridors (10,618 sq km), and a 1 m Pléiades tri-stereo DTM of Mt Karthala, Grande Comore, assessed at 65 cm LE90 against 179 GPS ground control points. Geoimage states over 30 years of experience creating DEMs.