Geoscience Reference
In-Depth Information
2.3.3.Software setup
Our approach did not consist in developing a specific GIS but in adapting
an existing one to our hardware setup. We chose to run Quantum GIS on
the Immersion Ilight tabletop. Quantum GIS (QGIS) is a multi-platform
desktop GIS software that offers numerous features making it one of the
most advanced and user-friendly open source GIS.
QGIS supports a wide range of sources and data formats such as Shapefile,
WMS, WFS and raster images. Moreover, it provides several “Export”
capabilities such as paper outputs. QGIS offers classical visualization and
navigation features such as pan, zoom, rotate and various advanced tools
for editing data such as the “automatic layer simplification” feature. Users
can also analyze data through advanced statistical and geometric functions.
Finally, QGIS provides an efficient plug-in system, a feature we used for
augmenting it with advanced interaction techniques.
While QGIS provide many features and a user-friendly interface (
Figure
3
), it was developed for the PC and not for multi-touch tabletops. In par-
ticular, traditional graphical widgets (menu bar, docks, palettes, etc.) are
not very well suited for direct touch interaction on tabletops because they
suffer a number of drawbacks (Bailly et al. 2010):
•
Occlusion. The hand and the fingers may hide parts of the display.
•
Accuracy. The large surface area of finger-screen contact may induce
selection errors when touching graphical objects on the screen.
•
Lack of keyboard. In the absence of a keyboard, it may be difficult for
users to enter text, while keyboard shortcuts are not available for acti-
vating menu items.
•
Reachability. The length of the human arm being what it is, the menu
bar may be difficult to reach.
We thus propose novel techniques for simplifying the interaction with
QGIS on interactive tabletops in order to overcome the abovementioned
shortcomings and to allow technical and non-technical users to perform a
large set of tasks (including common navigation tasks, but also more com-
plex tasks such as editing, annotation or statistical analyses) by performing
simple gestures.
