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Fig. 6: Georeferenced images, damage accounts and assigned 
units 
Further on arbitrary units (fire-fighters, THW, police, Red 
Cross, etc.) can be assigned to the damage accounts. Using GPS 
data and mobile devices allows a live visualization of unit 
positions as well as the damage account they are assigned to 
(see Fig. 6) which is usually also their final destination. Using 
mobile devices enables workers in the field further on to send 
multimedia data (images, videos or text messages) to the 
useTable. This is used to visualize and describe the situation 
with geo-referenced data in more detail (see Fig. 6). 
4.4 Network Coverage 
To fulfil the requirement of assisting the workers in planning 
mobile network creation the useTable offers the network 
coverage tool (see Fig. 7). Workers on the useTable can define 
the area that has to be covered as well as known obstacles like 
buildings, hills or trees. Based on this input data a Bresenham / 
A* / Connected Set Cover algorithm calculated the most 
suitable positions for antennas as well as the network coverage 
and signal strengths in the defined area (see Fig. 7). 
    
Fig. 7: Antenna positions and network coverage in a predefined 
area with obstacles 
4.2 Water Transportation 
Another tool specifically designed to plan water transportation 
is the so called pump tool (see Fig. 8). Using digital pen input 
for precise planning it allows comparing different routes for 
water transportation. After drawing an arbitrary route on the 
map the altitude profile of the route is calculated as well as the 
number of tubes, the number of pumps and the position of 
pumps. All results are then visualized on the map as well as in 
the pump tool window (see Fig. 8). After drawing and 
visualizing different routes the workers on the useTable can 
decide which one is most suitable and delete the others. Then 
assigned units begin to place tubes and pumps on the calculated 
positions in the field. 
    
  
Fig. 8: Pump Tool 
5. DISCUSSION 
As explained previously the development takes place in close 
collaboration with the intended end-users from THW. In 
addition to formative evaluation that guides the development we 
have also conducted summative tests with experts from the 
THW and discussed the system with members of the THW 
authority. In general the feedback has been very positive. 
Regarding the base technologies the increasing availability of 
commercial systems makes the creation of similar systems 
increasingly viable for many applications. 
5.1 Experiences 
While the feedback has been very positive it became soon 
obvious that the central improvements that triggered these 
responses were process improvements and not interface 
improvements per-se. That is, for the end-users it was not 
essential if the system features a multi-touch, tangible or pen 
based interaction method, but the advanced functionality that a 
computerized system enables. As discussed previously the 
multi-modal interaction techniques are key enablers of these 
process improvements, because conventional user interface 
techniques fail to address many of the basic conditions of group 
interaction and situation awareness, thus the computerized 
processes described above can only be realized because the new 
interaction techniques enable to design a system that fits the 
central requirements (and that were not addressable with 
conventional user interfaces). These observations confirm that 
for the development of usable systems based on advanced 
interaction techniques the user centred process of developing a 
real-world application is essential, because individual 
interaction techniques (if they themselves are well designed and 
usable) can only enable better systems. 
5.2 Process improvements 
Even small functional additions enabled by a computerized 
system (e.g. switching maps while keeping the data and 
annotations geo-referenced) caused enthusiastic responses and 
process improvements enabled by having all data in digital form 
(e.g. the calculation of the number of required pumps) lead to 
significant improvements in efficiency (in the example of