is that street names connected to the centre lines of roads and 
house numbers are part of the mapping and open up for con- 
nection to existing administrative databases. 
The map in 1:200 000 which covers Denmark in 4 sheets has 
been converted to digital form. The next edition will be 
updated purely digitally. The road centre lines of this map are 
at the moment being transformed into a road database by estab- 
lishing connections between the centre lines and all town 
names, CIP codes and information from the Danish Road 
Administration. 
Greenland 
All mapping activities in Greenland have been suspended due 
to lack of resources. Looking at the Northern Greenland Map- 
ping Project, all data capture is finished, and 34 sheets are 
published. 
The Faroe Islands 
The mapping project of the Faroe Islands is continued and at 
the moment 23 sheets have been plotted and 16 sheets have 
been published. 
The future 
At present a lot of test exercises are taking place in order to 
establish cooperation between the National Survey and local 
communities which are responsible for the large-scale technical 
mapping of Denmark. The idea is that the National Survey 
shall utilize information from the local communities in order to 
minimize productions costs. 
Lars Tyge Jorgensen 
THE CADASTRE 
Introduction 
Registration of land, titles,interests,mortgages,easements, etc. 
is divided between the National Survey and Cadastre and the 
offices of the Land Registry. 
In accordance with the Development Act, all alterations of 
boundaries are to be registered in the Cadastre. Alterations are 
registered on the basis of documents worked out by licensed 
land surveyors in private practice who also do the surveying 
required. In the National Survey and Cadastre the areas, etc. 
are entered in the register, and the new boundaries are drawn 
on the cadastral maps. When alterations of property have been 
registered, the keeper of the Land Registry and the tax assess- 
ment authorities are notified. 
The cadastral register has been on edp for six years. 
A conversion of the maps to digital form is going on. 10-15 
per cent is on a digital form today. 
Cadastral maps 
In Denmark the entire country is covered by cadastral maps. 
The maps have been kept up-to-data with registered alterations 
of property since the start of the Cadastre in 1844. The scale 
of the maps is 1:4000 or larger. 
The majority of the maps are "island maps", i.e. every village 
is on a separate map. The maps were originally measured by 
plane table survey, and they have all been redrawn one or more 
times. The towns were registered for cadastral purposes for the 
first time 1865-1875. The maps are in scale 1:800 and are ba- 
sed on traverse survey. 
73 
Since the turn of the century new plans have been produced on 
the basis of terrestrial surveys and since 1960 on the basis of 
photogrammetric surveys. Surveys carried out after 1934 are 
normally linked to the Danish national grid. 
The cadastral maps are mainly intended for the public registra- 
tion of land, but they are also used for administrative purposes, 
planning, etc. by authorities, public institutions and by private 
persons. 
Reference network 
Control points for cadastral measurements have been coordina- 
ted using bundle adjustment with added parameters. 
The result of the coordination is a densification of the existing 
2 km net of triangulated points down to a density of approx. 
400 m. The photo scale is preferably 1:8000 - 1:10000 and the 
overlap 60/30. 
The accuracy is tested in the field by measuring distances 
between coordinated points using edm. The standard error on 
a photogrammetrically coordinated point is less than 5 cm. 
In connection with the conversion of the maps to digital form 
it was agreed that an accuracy of 10 cm on the control points 
was sufficient for that purpose. This was obtained using a 
photo scale of 1:18 000. 
An edp-based register of the coordinates for control points - 
about 360 000 points - has been established. The observations 
are being converted in connection with the conversion of the 
cadastral maps. 
Present activities 
A conversion of the cadastral maps to digital form is going on. 
The conversion is not just a matter of digitizing the existing 
maps. 
The "island maps" were not measured on a common reference 
system. In order to relate the contents of the maps to the 
reference system of today, you have to partly reconstruct the 
maps. Information from the field, in the form of orthophotos or 
photogrammetrically produced line maps, and existing mea- 
surements from the updating procedure are used in this connec- 
tion. 
The accuracy of the new map depends very much on the accu- 
racy of the control points and the amount of measurements 
used. 
As the accuracy is also expensive, you will have to watch out 
for a balance. 
Today we have given up the aerotriangulations for the renova- 
tion of the control points. We have found that a recalculation 
of the points from the existing observations, supplemented with 
a few new, will give us an accuracy sufficient for this purpose. 
We also use less measurements and more digitizing of the old 
maps today than we intended when we started in 1986. 
These changes mean that covering the whole country with di- 
gital cadastral maps is today calculated to cost less than half 
the price that we anticipated 6 years ago. 
The conversion is partly financed by user-payment.Therefore 
the speed of the conversion is very much depending on user 
HO Oy < Bod 
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