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software, cable of checking and displaying these kinds of errors
that oprators very often makes. Now such software has been
developed by the National Survey and is delivered to the produc-
ers to be used in the internal quality control before delivery to the
National Survey.
Upgrading to TOP10DK.
Upgrading TOP10DK is done according to the specifications. The
topological rules are specified carefully, and the National Survey
tests whether data fulfill the rules. No area is allowed to be partly
part of another area. The distance between points is at minimum
1.00 metre. If two points are situated closer to each other than this
minimum distance they have to be joined. This is valid in all three
dimensions. All centre lines of roads have to form a network. No
rounding error of just one centimetre is allowed. All points must
have a code of origin. If the producer edits one point within an
object the code of origin must shift because the production
method has shifted from photogrammetry to editing. Last but not
least data must be readable, i.e. the exchange format must be
written correctly. Since there is no internationally accepted
exchange format the producers very fast accept to use the software
offered by the National Survey because it automatically writes
files in a format accepted of the National Survey.
6. UP-DATING TOP10DK
One basic idea of TOP10DK is to transfer the work of collecting
updating data from the National Survey to the local communities,
were the technical maps are administrated and updated. The idea
of making a hierarchical standard for technical maps is to make it
possible to extract updating data from these large scale technical
maps by using the same feature coding as used in the small scale
maps.
If a change is found and stored it in TOP10DK, it can be used in
all map series and there fore time and money is saved. A major
problem is that TOP10DK and the series of analog maps at the
National Survey are not hierarchical according to feature and
content! The resources to collect updating data for the analog
maps are very limited and tailored to this specific task. During the
last four years efforts have been made to convert production
methods of topographical maps and nautical charts to digital
means, and now the base map scale 1:25.000 is updated digitally.
In principle this should make it easier to combine these different
data collections, but in practice little have been done to ensure
exchange of data between the different production lines. The
decision of establishing TOP10DK was combined with the clause
that the establishing period should be short. But when TOP10DK
does exist in an area what will happen when the base maps in the
same area are to be updated? This situation occurs at Bornholm,
where TOP10DK exists and the base map is to be updated this
year. The updating method of the map 1:25.000 involves digital
orthophotos and for obvious reasons it seems natural to involve
digital photogrammetry and a method to record changes in the
scanned foils of the base map. These changes should be classified
in categories of kind of object deleted and kind of object added.
Since the updating of the base map is done using digital photo-
grammetry one possible solution could be to involve digital
photogrammetry while updating TOP10DK. A working group is
formed to organize a full scale test on Bornholm this autumn.
393
7. TIME SCEDULE
Time schedule is normally defined in the tender material, but of
course the National Survey is willing to change schedule when
negotiating the contract. Having experiences from five contracts,
it can be said, that none of the producers has been able to fulfill
the contract according to time schedule. The consequences of this
has been that the internal plans of work load at the National
Survey have been shifted with great inexpedient consequences for
the (very small) internal production. The contracts contain an
inbuilt possibility to exceed the time schedule up to thirty days. If
the schedule passes more than that the producer must pay a fine
figured out by the time delay.
8. THE FUTURE
In the years to come the establishment of TOP10DK and updating
the base map will coincide in major parts of Jutland. The way how
analog map series and TOP10DK interact must come to some
solution very soon. If a solution is not found the whole idea of
establishing a basic database might be lost.
9. REFERENCES
Bengtsson, T. and Jorgensen, L.T., 1989. Concept and Preparation
of a Spatial Information System for Denmark, 42. Photo-
grammetrischen Woche, Stuttgart.
Specification for Technical Maps, (english version 1993).
FK-STANDARD, (in danish), Published by Kort- og Matrikel-
styrelsen, Copenhagen 1993.
Arildsen, L.M., 1993. Denmark's Topographic Base Map Database
TOP10DK, AM/GIS 1993- Lillehammer.
Aarhus Projektet Fase I, (in danish) Kort- og Matrikelstyrelsen
1993
Aarhus Projektet Fase II, (in danish) Kort- og Matrikelstyrelsen
1994
FK-STANDARD, second edition (in danish), Published by Kort-
og Matrikelstyrelsen, Copenhagen 1995.
TOP10DK Specification, (english version 1995) Published by
Kort- og Matrikelstyrelsen, Copenhagen 1995.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
