ArcticDEM for safer UAV flights
Recently new digital surface model ArcticDEM Release 3 has been released for wide list of territories - Alaska, Baffin Island (Canada), Svalbard (Norway), Iceland, Novaya Zemlya (Russia) and Franz Josef Land (Russia) enabling safer UAV mission planning.
This is exciting news for UAV industry, as UAV usage has increased in Arctic region during last 5 years, but previously available public elevation data for hard-to-reach regions was outdated and imprecise.
Automatic mission planning is not safe without precise elevation data, as it is not possible to accurately predict real altitude above ground level (AGL) of the aircraft during flight. To fly a multirotor UAV on a photogrammetry mission with good ground sample distance (GSD) or magnetic survey when it is needed to carry a sensor few meters above the terrain - precise elevation data availability is vital for safe operation of aircraft.
To illustrate the difference see the screenshot example (Figure 1) from Svalbard (Norway). On the left side (marked with green) the area has the new ArcticDEM loaded, comparing to right side - elevation data gathered from previously available open source elevation data. From the mark in the middle it can be seen, that the difference between ArcticDEM and older open source terrain elevation data is 30 meters!
Figure 1. UgCS screenshot comparing ArcticDEM and other open source elevation data
There are two digital elevation model (DEM) file types available: strips and mosaic.
Strip DEM usually are long, but narrow images corresponding to how satellite took an image of the location. Strips contain a relatively large number of empty spaces – places where the data is missing. Also, data in these files can have xyz offset. This offset specified in corresponding metadata file but corrections have not been applied to the strip DEM files.
Mosaicked DEM files are compiled from the best quality strip DEM files which have been blended and feathered to reduce void areas and edge-matching artefacts. Mosaic have higher accuracy and data reliability comparing to strip files. Mosaics are recommended, however, they are harder to get as it is necessary to find out which file is needed and it needs to be loaded.
For obtaining the ArcticDEM data, one option is to get strip DEM files from the ArcticDEM Explorer: http://arcticdemapp.s3-website-us-west-2.amazonaws.com/explorer/. The data can be exported from the site as a .tif file and then imported in UgCS.
Alternatively, more detailed mosaic data can be downloaded from the ArcticDEM directory ftp://ftp.data.pgc.umn.edu/elev/dem/setsm/ArcticDEM/ or: http://www.arcgis.com/home/webmap/viewer.html?layers=db38a951a2b643478a942ab22cd78fc6.
DEM data import is enabled for UgCS Pro and UgCS Enterprise licence owners.
Special thanks to ArcticDEM project team, who made this valuable asset available for everyone!
(Image source: http://pgc.umn.edu/arcticdem)