7B-3-2 
With these new interfaces more and more applications 
for moving computation from static desktop systems to 
the mobile user are coming into sight. Through this evo 
lution, which comes along with the growing acceptance 
of Internet and multimedia, such a stagnating and sat 
urated software technology as Geographic Information 
Systems (GIS) has been pushed on the move. Start 
ing with the first portable pen-computers, field-based 
GIS have become a valuable and essential tool for field 
data acquisition. Meanwhile, various mapping systems 
are on the market which, coupled with a differential 
GPS (Global Positioning System) sensor, enable the 
user to define or modify geo-objects for GIS databases. 
Surprisingly, despite of the powerful hardware equip 
ment, even the digital acquisition of application specific 
attributes is sometimes underrepresented within such 
software systems. As visualization and graphic displays 
of spatial data are helpful means to improve the data 
collection process [MacEachren, 1994], the use of ad 
ditional services and methods to support this process 
are required by the user. Besides knowledge-based di 
agnostic tools and automatic plausibility control, im 
proved interfaces can augment the reality by overlaying 
graphics, text and sound. The use of additional sen 
sors, speech-control and the online access to Web-based 
data sources rounds out the number of new possibili 
ties. In the following, some utilization’s of these new 
approaches in the field of spatial information technolo 
gies will be set out. 
2.1 Augmented Reality supporting mobile 
mapping 
Field data acquisition is one of the most cost and time 
consuming part in the process of building or updating 
a GIS database. Therefore any kind of add-on informa 
tion which helps the data collector to improve or speed 
up his task is of high value. Especially when dealing 
with spatial objects (e. g., field boundaries) informa 
tion that supplements the real world is very suitable 
to support the mapping process. Augmented Reality 
devices like optical or video see-through displays which 
were pioneered by [Sutherland, 1968] are able to enrich 
the user’s view by overlaying those digital vector/raster 
elements. In contrast to the use as supporting means 
for Interior Design and Modeling [Ahlers et al., 1995], 
Computer-Aided Surgery and Training [Mueller et al., 
1998; Rosen, 1996], Entertainment, Military Train 
ing [Urban, 1995], Engineering Design and Mechan 
ical Repair [Rose et al., 1995], only few applications 
in Geoscience have been applied [Egenhofer & Kuhn, 
1998]. To enable features like overlaying geometry, the 
user must be equipped with a DGPS receiver and an 
orientation tracker (e.g., gyroscope, magnetometer, in 
clinometer) to measure the orientation of the display 
unit. As the user wears this device as a head-mounted 
display, the tracking system registers yaw, pitch and 
roll of the users head. Together with the coordinate 
and orientation information the system knows how to 
fit the vector geometry exactly matching above the real 
remote GIS database 
& DGPS base station online field GIS 
Figure 1. Wearable Networking for field GIS 
scene. We don’t want to conceal, that the technologi 
cal development of the feature will be one of the most 
challenging tasks for the future. Two main benefits for 
the user are obvious: 
- comparison between stored GIS dataset and real 
conditions 
— displaying invisible information 
The first functionality is particularly useful during 
the update process of spatial data. Often the user does 
not know if the geometry of the spatial objects have 
changed or not because of the lack of an three-dimen 
sional terrain impression. To detect modifications of 
field boundaries he has to change his position and pace 
off the area while comparing the actual GPS position 
with the existing geometry displayed on the screen. 
Detecting the potential deviations between stored GIS 
dataset and real conditions would be much more easier 
if the work was supported by this new computer inter 
face. Another fascinating progress in field work is the 
visualization of invisible features (underground condi 
tions). Field workers are now able to fade in drainage, 
soil horizons etc. without averting from the terrain and 
loading a new layer onto the screen map. This is a new 
kind of intelligent user support, where various required 
information can be displayed on demand. 
2.2 Intelligent data access via wireless 
networking 
To reach sufficient GPS position accuracy the use of a 
differential correction service is essential. Different car 
rier systems for data broadcasting are available on the 
market. Along with the improvements in wearable hard 
ware devices, new powerful data transmission system 
(e.g., GSM, DAB, Wave-LAN) have come up. Mean 
while, the bandwidth (sometimes limited by reach and 
coverage) is wide enough to provide a sufficient Inter 
net connection to exchange large data files. Even the 
transmission of audio and video signals is no longer im 
possible. With the integration of real-time DGPS into