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International Archives of the Photogrammetry. Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
remaining. objects belonging to the topographical or the large-
scale databases respectively are registered in accordance with
the two basic specifications. On the long view, the full
implementation of the COT concept will influence the
specifications for both the topographical and the large-scale
databases.
The COT are selected as being the most important objects as
regards e-government and the spatial data infrastructure. A
similar classification of objects is found in the INSPIRE
initiative (European Environmental Agency, 2004), where
administrative units, transport, hydrography etc. are defined as
priority common basic data. Surprisingly, building are not
found as basic data in the INSPIRE proposal but included as
commonly used thematic data. However, buildings are
considered extremely important and recorded in greater detail in
Denmark and consequently included in COT.
5. PLACE NAMES AND POINTS OF INTEREST
(SNSOR)
Names of cities, road names and POI are important information
when geo-spatial data are in use, either on printed maps, as part
of an Internet service or in GIS analyses. Accurate and up-to-
date information on names and POI is crucial for Internet
services such as travel planning, emergency turn out etc.
The TOPI0DK concept comprises a separate database for place
names and points of interest (SNSOR) that is closely linked to
the geometry database. The SNSOR has become increasingly
important as the demand for accurate and up-to-date
information in Internet services is intensified.
5.1 Points of Interest
Points of interest are locations that are of general interest or
locations that are of interest for a thematic visualisation of geo-
data. Examples are museums, churches and railway stations as
POI for general purposes or campsites on a map for recreational
purposes.
The database is structured in such a way that a copy of the
geometry, for instance the outline of a church is imported from
the geometry base to the SNSOR database. Subsequently, the
word "church" is attached to the centre of the building
geometry. The physical placement, font, and size of the letters
of "church" are decided during the visualisation process.
An automatic geo-coding process is introduced by defining an
address point of the entity. It may be thc centre of the building
or it could be any point related to the surface defining the
entity.
Most information received from external sources is in one way
or another related to the address of the entity. It is generally
agreed that the address is one of the most important keys in the
geo-coding process.
Received information from external providers is compared with
an address register containing official addresses and
corresponding locations, i.e. an address points (x, y). If the
address of an incoming entity matches the address in the
register the coordinates are attached to the entity and its
attributes and stored in the database. For certain institutions a
hit rate of up to 97% percent is achieved with automatic geo-
607
coding. The remaining few percents are evaluated manually,
subsequently geo-coded or rejected as being invalid.
POI are classified as regards importance and availability and
from this the revision frequency is decided. The system is under
continuous development in order to automate the process.
Through dialogs with information suppliers the system is being
expanded and improved in order to minimise the manual
interaction.
5.2 Place Names
Place names are treated differently. A city name, for instance,
refers to a specific geographical area. The area is defined by a
polygon encircling the city area and the name is attached to this
surface. The updating procedure then comprises a check of the
polygon whether it still holds the entire city area. The revised
geometry database showing built-up areas is used in this
process.
Some place names are authorised by the Danish Government.
New place names are normally suggested by local authorities
and must be accepted by a governmental committee. Members
of the committee represent government departments and
universities. An updated register holds the authorised place
names.
The co-operation with The Statistics Denmark (statistical
department) is important in order to ensure that city areas
(statistical units) are defined unambiguously and that the
various geo-spatial databases in the country operate with the
same and updated version for use in GIS as well as statistical
analysis.
5.3 SNSOR Update
Contrary to the TOPIODK geometry and the elevation model
the register of names and POI is updated continuously. The
update frequency for each type of POI depends on type of
information, priority and availability. The priority is decided
from the use of the specific POI or place name. For instance, a
POI that is used in the travel planning application is classified
as basis data and kept under continuous surveillance.
The register is strongly dependent on the external sources and
agreements concluded between KMS and data providers.
6. DIGITAL ELEVATION MODEL
The third component of the TOPIODK concept is the digital
elevation model (DEM). It is created from data of different
origin and aimed to fit the general specifications of the database
and to be used along with the various map products, separately
or in GIS-analyses. At present it is produced in a 25-meter grid
and as 2.5 meter and 5 meter contour lines.
6.1 Basic Data
Three types of data form the basis of the elevation model:
e 2.5 meter contours from old map sheets
e (Certain object types from the geometry database
e. Spot heights, i.e. points with local max. or min.
elevation together with selected points that locally
describe the shape of the terrain surface.
