Devon Island
Rover Navigation Dataset

Lidar Scans and Panoramic Images

Lidar scans and panoramic images were acquired at 37 different locations on Devon Island with an Optech ILRIS3D-ER. The point clouds from these 360° scans contain millions of points spread out over a maximum range of about 1.5km with centimeter-scale position accuracy. A camera on the lidar also allowed panoramic images to be collected. Before each scan, the lidar was leveled with a two-axis bubble level to an accuracy of about 1 degree for one standard deviation. To obtain the heading of the lidar with respect to the Easting, a target was setup about 100 metres away and scanned. Knowing the GPS locations of the target and lidar, the orientation of the lidar could be determined with an accuracy of 1 degree for one standard deviation.

Ground-Truth

Ground-truth positions of the lidar scan locations were obtained from a Garmin GPSMAP 76CSx. After averaging GPS measurements for several minutes at each scan location, the standard deviation of position measurements was estimated to be 1m.

The date and time of each scan are given in the following table. Each scan took at least 30 minutes to collect so we report the time that the scan was started in Central Daylight Time (CDT). The start times are accurate to within 30 minutes.

Orbital Maps

Orbital maps of Devon Island were obtained on December 11, 2009 from Geobase---a repository of up-to-date geospatial data for Canadian territory maintained by the Canadian Council on Geomatics. The maps were projected from North American Datum 1983 (NAD83) latitude/longitude coordinates to the Universal Transverse Mercator (UTM) coordinate system using the commercial program Global Mapper. The elevation data in the maps is expressed in the Canadian Geodetic Vertical Datum 1928 (CGVD28). Two maps are provided:

1. a 1:50,000 high-resolution map with each pixel covering an area approximately 12.5 x 25 meters. This was derived from Geobase maps ``058h06'' and ``058h07'', and
2. a 1:250,000 low-resolution map with each pixel covering an area approximately 50 x 100 meters. This was derived from Geobase map``058h''.

The dataset is organized into two subsets:

• Lidar Scans: 3D lidar scan point clouds, panoramic images and ground-truth UTM scan locations,
• Orbital Maps: 3D maps of relevant areas of Devon Island,

Lidar Scan Point Cloud

Filename: A[Scan #].txt
This file contains a 3D point cloud obtained from the scan at position [Scan #] in the following format:

where the coordinate frame origin is at the laser center, the x-axis points East, the y-axis points North, the z-axis points up, and the reflected beam's intensity ranges from 0 (weak) to 255 (strong).

Lidar Scan Panoramic Image

Filename: A[Scan #].png
This file is a 360 degree panoramic image of the local terrain at scan position [Scan #]. Each image has been cropped such that the rightmost pixels coincide with the local Easting.

Lidar Scan Ground-Truth

Filename: groundtruth.txt
Ground-truth UTM positions (all are UTM zone 16X) acquired from a Garmin GPSMAP 76CSx in the following format:

Orbital Maps

Filenames: "mapHiRes.txt", "mapLoRes.txt"
These files contain orbital map data in UTM coordinates. The UTM zone for these maps is 16X. They are provided in the following format:

Matching Scans To Orbital Maps

Lidar scans can be matched to the orbital maps to globally localize the lidar scan origin. As given, the maps are much larger than any individual scan. It may therefore be of interest to trim the maps (see plotPointsOnMap.m) before attempting to match.

Scans 24, 25 and 29 are not fully contained by the high-resolution orbital map ( eg. try executing plotPointsOnMap(24,'mapHiRes') ). Data for this area of Devon Island is not currently available from Geobase.

Plotting Scan Points On Images

Scan points can be plotted on the panoramic images (see plotPointsOnImage.m) knowing the lidar's camera parameters. The horizontal and vertical fields of view of each image are respectively 360° and 45.5°. East (0°) is the rightmost pixel. The middle vertical pixel is zero degrees, with the exception of the following scans, which were tilted:

The dataset may be downloaded as a zip archive from ftp://asrl3.utias.utoronto.ca/Devon-Island-Rover-Navigation/.

Lidar Scans | compressed size: 1300MB, extracted size: 4480MB

Orbital Maps | compressed size: 33MB, extracted size: 312MB

Important note: The dataset provides ftp download links. Some browsers no longer enable ftp links by default and you need to change the settings if you want to download using the browser. Using the wget command is an alternative to avoid the browser.

The following tools are provided for the convenience of dataset users. Run them in the dataset's root directory.

Matlab Scripts

• loadGroundtruth.m Loads UTM position ground-truth for a scan into Matlab variables.
• loadOrbitalMap.m Loads an orbital map into Matlab variables.
• loadScanPoints.m Loads point clouds of scans into Matlab variables.
• plotPointsOnImage.m Plots horizon scan points onto a panoramic image.
• plotPointsOnMap.m Plots scan points onto an orbital map.