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THE HARMONISATION CHALLENGE OF CORE NATIONAL TOPOGRAPHIC 
DATABASES IN THE EU-PROJECT GIMODIG 
S. Afflerbach“, A. Illert*, T. Sarjakoski” 
* BKG, Federal Agency for Cartography and Geodesy, 60598 Frankfurt, Germany - (sabine.afflerbach, 
andreas.illert)@bkg.bund.de 
? FGI, Finnish Geodetic Institute, Depart. of Geoinformatics and Cartography, 02431 Masala, Finland - 
tapani.sarjakoski@fgi.fi 
KEY WORDS: Transformation, Visualization, Scale, Reference Data, Global, Mobile, On-Line, Real-Time 
ABSTRACT: 
The project GiMoDig (Geospatial Info-Mobility Service by Real-Time Data Integration and Generalisation) started in November 
2001 and is funded by the European Union. With a duration of 3 years this EU-project has the goal to develop methods for 
harmonisation, generalisation and visualisation of national topographic data sets for mobile users in real time. The project partners 
are the Finnish Geodetic Institute as a project coordinator, the National Mapping Agencies (NMAs) of Denmark, Finland, Sweden 
and Germany and the University of-Hanover, the Institute of Cartography and Geoinformatics. One of the tasks in the GiMoDig 
project is to define a Global Schema for the core national topographic data sets. For this purpose an inventory on the national 
databases is prepared to list the differences in data availability and data modelling. Based on that inventory, a selection of feature 
types suitable for Location Based Services (LBS) is made. The idea is to use the least common denominator as selection criteria but 
this subset already lacks some important feature types. Finally all features that arc supported by a majority of national data sets are 
integrated in the Global Schema. The Global Schema is defined with a detailed description about feature type, attributes, collection 
criteria and geometry type. All necessary information about harmonisation operations are given to be able to transform the 
topographic data from the national schema into the Global Schema. Further scrutinizations of test data lead to an improvement and 
adaptation of the Global Schema. 
I. INTRODUCTION 
Location Based Services (LBS) are becoming more and more 
important in every day life. They are services that enable a 
mobile user when using a mobile device, e.g. PDA or mobile 
phone to retrieve spatial information related to his actual place 
concerning his special wishes. Depending on the usage and 
location the map visualisation can be performed in various 
ways. In any case it conditions that the mobile device has the 
functionality of being locatable, e.g. via radio location in the 
mobile network (GSM or UMTS) or via GPS if more precise 
location destination is wished. 
Users in foreign environment without any paper map have the 
possibility to orientate with any problems due to the LBSs. 
Additionally, they get important information, e.g. on sights. 
Geospatial data plays an important role in the LBSs. With their 
help specific locations can be found more easily as a direct 
relation to the spatial surroundings is given. But topographic 
information is of value only when linked to other information 
relevant to the service. Recent studies have found out that users 
require morc object orientation, nonspatidl attributes (names, 
road types etc.), metadata, history and temporal queries, easy 
aggregation (thematic, geometry), linkage with other data, and 
unique identification code and conformity to standards like 
OpenGIS, CEN, ISO. Interoperability with other datasets in 
terms of semantics, spatial reference, data model and language 
is getting more and more important. 
The field of applications based on geospatial data is wide. It 
comprises city guiding, routing like navigation systems in cars. 
But the importance of LBS increases also in other fields, e.g. 
for rescue services. With precise positioning police, fire brigade 
or emergency doctors are able to render assistance to an injured 
person much faster. Even when hiking in nature it can be of 
great importance to have LBSs with geospatial data as 
background information. 
2. EXISTING SOLUTIONS 
Up to now most of the available LBS are offline solutions with 
raster maps. However, raster data is static concerning the 
resolution and the content of the image with no or only minimal 
flexibility. When zooming in, either the same data is viewed 
with the same resolution and therefore in a much more coarse 
way or a new data set has to be loaded. In addition, raster data 
has the disadvantage of covering a huge data size and therefore 
requires a lot of memory. In the case of offline solutions the 
data has to be stored locally on the mobile device (PDA, mobile 
phone) which leads in most of the cases to the fact that not all 
necessary raster data can be stored on the mobile device. The 
user is forced to choose the relevant map part of his next trip 
and to save only that particular part of the whole map on his 
mobile device. As a consequence new data has to be provided 
for each new usage situation. The old data has to be removed 
from the mobile device in order to make room for the current 
map part. A lot of manual work has to be donc. 
There exist some applications based on vector data. They are 
often visualised in the XML-based (eXtensible Markup 
Language) vector format SVG (Scalable Vector Graphics). 
However, map applications based on national topographic 
vector data as map base do not exist at the moment despite of 
the fact that these national geospatial data sets are usually 
available for the whole country. One of the reasons for this lies 
in the lacking agreement of the national data suppliers. In order 
to create homogeneous data sets for cross-border applications a 
big effort has to be made to create them directly from 
heterogeneous national data sources. Updating data directly