From Oslo to the Ice: Surveying Norway

Per Chr. BRATHEIM and Bjørn Geirr HARSSON, Norway

Key words: Surveying, Triangulation, Norwegian Mapping Authority

SUMMARY

Norway has a landscape characterized by tall mountains, deep valleys and long fjords.

Surveying and mapping Norway proved very challenging before the advent of satellite

geodesy. The Norwegian Mapping Authority was established in 1773. One of the most

important tasks was to establish a geodetic control point network as a base for mapping and

surveying. The surveying methods and equipment developed gradually over the 200 year time

period before satellite geodesy changed the scene. As a result, the entire country has been re-

measured several times in order to meet increasing demands for accuracy. The efforts of our

predecessors to establish a geodetic control network in Norway and other countries are hugely

impressive. The work involved in surveying and mapping has produced untold benefits for

society and societal development.

From Oslo to the Ice: Surveying Norway

Per Chr. BRATHEIM and Bjørn Geirr HARSSON, Norway

1. BACKGROUND

The Kingdom of Norway spans an area of 324,000 km2. The country is situated at the top of

Europe between 58° and 71° North, with a landscape characterised by tall mountains, deep

valleys and long fjords. Surveying and mapping Norway proved very challenging before the

advent of satellite geodesy.

Norway was in a union with Denmark until 1814. The political relationship with neighbouring

Sweden became palpably tense when Gustav III ascended to the Swedish throne in 1771. The

King of Denmark and Norway deemed it necessary to prepare should war break out. The

Danish-German general Wilhelm von Huth was tasked with determining how to best counter

a military threat from Sweden. Von Huth's proposal was to map Norwegian areas along the

border with Sweden and, in 1773, the Norwegian Border Survey (Norske Grændsers

Opmaaling) was founded. Since then, this state-owned agency has been continually active and

has undergone successive name changes, including the Norwegian Geographical Survey

(Norges Geografiske Oppmaaling) and, as it is currently known, the Norwegian Mapping

Authority (Kartverket).

Mapping of Southern Norway's border areas began promptly, before the existence of a control

network. The mapping was undertaken utilising the plane table method, and it soon became

clear that combining the individual map sheets would be problematic. For this reason it

became necessary to establish a geodetic control network.

Figure 1. One of the first maps of the area around Svinesund.

Figure 2. Geographic circle

2. THE FIRST CONTROL NETWORK

Work commenced in 1779 to establish a geodetic control network from Kongsvinger, east of

Oslo, to Verdal, north of Trondheim. Points were determined by means of triangulation, for

which geographic circle was used. Astronomical measurements were also made at some of

the points. Baselines were measured to determine the scale of the network. The first baseline

measurements were carried out in winter on frozen lakes with wooden measuring rods. The

work involved in establishing the first geodetic control network continued for 5 years and was

completed in 1784. Between 1785 and 1799, triangulation was carried out along the coastline

of Southern Norway from the Trondheim Fjord to the border with Sweden.

In the years that followed, there was a great deal of mapping and surveying activity in

Southern Norway. From 1828, a number of control points were

established along the coast of Northern Norway to form a basis

for coastal mapping. For this purpose, Norway acquired its

first theodolite, an Ertel.

3. POLITICAL CHANGES IN 1814

The peace treaty that signalled the end of the Napoleonic wars

in Europe resulted in Norway and Sweden forming a personal

union in 1814, while Denmark lost all authority in the country.

This period was marked by political turmoil, and very few

resources were available for mapping and surveying. Tensions

subsided after 1814, but triangulation was not performed to

any significant extent in the ensuing years. Instead, detailed

mapping of Eastern Norway became a priority.

Figure 3. Ertel

theodolite 1826

Figure 5. Repsold theodolite, in

use during the Struve Arc

measurements

4. MERIDIAN ARC MEASUREMENTS

The Norwegian part of the Russian-Scandinavian

meridian measurement (the Struve Geodetic Arc)

was undertaken over the 1845-1850 period. 15 main

station points were established from the Finnish

border to the end-point at Hammerfest, as well as a

10-point extended network around the Alta baseline.

These points were used as a basis for surveying and

mapping in this area for more than 100 years.

The European meridian measurement was carried out

from 1864 to 1883 and ended at Rindleiret baseline

north of Trondheim. But this meridian measurement

never really concluded. It was characterised by

continuous improvements with respect to instruments

and measuring methods.

An overview map from 1876 shows that, over a

period of 100 years, most of Southern Norway was

dotted with geodetic control points. Besides for the

points included in the Struve Geodetic Arc, control

points were only established along the coastline of

Northern Norway.

Figure 4. The Struve Arc monument in Hammerfest 1928. Astronomers Hans Jelstrup and

Gunnar Jelstrup are pictured in the background in front of the observation cabin for

astronomical measurements.

Figure 6. The national control network in 1876, after 100 years of surveying.

Figure 7. Baseline measurement with invar wire

Figure 8. Geodesist L. Bockmann with the Laser

Geodimeter

5. THE MODERN FIRST ORDER NETWORK IN NORWAY

Quality requirements became more stringent during the 19th century. Initially, points were not

permanently marked and only stone or wooden markers were used. From the 1840s, iron bolts

were hammered into the bedrock or into large boulders to mark the points. The method of

least squares was adopted in 1872 for calculations. Using this method, it became possible to

objectively dismiss dubious measurements.

Work on the modern first-order network got underway in 1906. New Bamberg theodolites

were procured. The points were to be marked with iron bolts, and new requirements were

introduced for constructing trigonometrical stations. Stricter requirements were also

introduced for measurements and calculations. In an article from 1912, Klingenberg, the head

of the department at that time, wrote that very little of the triangulation work prior to 1906

conformed to the new quality requirements. In other words, the entire country would have to

be measured again!

The work started in the south-eastern part of Norway. Several new baselines were established,

and measurements for these were performed using Invar wire. Astronomical measurements

were also carried out at a number of key

points.

Over time, the cumbersome and heavy

Bamberg instruments were replaced with

Wild T3 theodolites. From 1958, test

measurements were conducted using the

Tellurometer micro-distancer. These

instruments utilised electronic waves.

Throughout the 1960s, distance

measurement was employed in the first-

order network instead of angle

measurement. Later on, a Laser Geodimeter

was used for long distance measurements.

Figure 9. The flagpole at

Kongsvinger Fortress

Figure 10. Oslo Observatory Figure 11. Professor

Cristopher Hansteen

6. NGO1948

After more than 40 years, the southern part of Norway had been fully surveyed.

Comprehensive calculations of everything measured were then carried out, and this signalled

the start of Norway's first national geodetic datum – NGO1948. New areas were calculated in

NGO1948 as their measurements were completed. Measurements for the modern first-order

network were completed in 1969, and calculated in NGO1948 after more than 60 years of

work. By around 1995, approximately 50,000 detail points were incorporated into NGO1948

to serve as a basis for mapping and surveying.

7. GEODETIC DATUMS AND MAP PROJECTIONS

Beginning in 1779, a coordinate system was established

with a fundamental point at the flagpole at Kongsvinger

Fortress. At that time, however, no consideration was given

for map projection. A right-angle coordinate system was

used which did not take the curvature of the Earth into

account.

This was of no particular consequence for the mapping of

Eastern Norway, but the need for a map projection to avoid

excessive distortion on maps became apparent far east and

far west of the prime meridian through Kongsvinger

Fortress. Therefore, in 1817, a collaboration was entered

into with Professor Christopher Hansteen at the Royal

Frederik's University in Christiania (Now the University of

Oslo). Professor Hansteen was appointed Director of the

Norwegian Geographical Survey, a title he held for 55

years.

In 1828, Cassini's transverse cylindrical projection was

adopted on recommendation from Hansteen, where the

flagpole at Kongsvinger Fortress continued to serve as the starting point.

Christopher Hansteen founded the Christiania (Oslo) Observatory in 1834, from where he

carried out numerous astronomical observations. The fundamental point was moved from

Kongsvinger to Christiania Observatory in the 1840s. Bessel’s ellipsoid combined with a

Figure 12. Dyrhaugstind peak Figure 13. Transportation on horseback

Gauss-Krüger map projection with 8 axes was adopted in the early 1900s. This system

remained in use until the EUREF89 and UTM systems were introduced in the 1990s.

8. FIELD WORK

As mentioned earlier, establishing a control network in Norway was an exacting process. The

most important points had to be affixed to the highest mountaintops where a good line of sight

was possible in all directions. Accessing the points was time-consuming, and often hampered

by inclement weather. Moreover, only limited resources were available to perform the work.

200 years ago, Norway had no mass transport system. Cartographers and surveyors were

forced to commission transportation, either by boat or, for areas with traversable roads, by

horse and carriage. Journeying from Oslo to Tromsø took several weeks. To get from the

main road out into the field, they frequently engaged the services of local porters, preferably

with horses whenever possible.

During the latter half of the 19th century, railways were built in Southern Norway. This

period also saw the creation of steamship routes along the coast and on the larger lakes. The

Norwegian Coastal Express company (Hurtigruten) was founded in 1893. Road networks

were also constructed at this time. These made it easier to travel from the office in Oslo out to

the work area, but there was still a need for local assistants to transport the equipment.

Surveyors set up tented camps in proximity to where they worked. When surveying mountain

peaks, they stayed in tents overnight close to the summits in order to make the most of periods

with favourable measuring conditions.

Figure 14. Summit tent on Dyrhaugstind in 1931 Figure 15. Ascending

Dyrhaugstind

Figure 16. Poor road conditions at Hardangervidda, 1964

Notwithstanding, work could still take an extremely long time in the most impassable and

weathered regions of Norway. An example of this was the measurements of Dyrhaugstind

peak in the western section of Jotunheimen. Work on the first-order surveys commenced in

1923, but was frequently hampered by inclement weather. The situation repeated itself in

1924. In 1925, Major Grinaker and his assistants eventually completed the first-order surveys

after several weeks of effort. Kristen Gleditsch conducted supplementary measurements of

Dyrhaugstind peak in 1931. The weather was favourable and Gleditsch and his assistants

completed the work within one week. While descending the mountain, Gleditsch fell and

broke his leg. He was carried down to the main camp by his assistants and convalesced in

hospital for eight weeks. Second-order surveys were completed by Captain Schive in 1934,

this time without any significant complications.

Figure 18. Geodesist John Sundsby at Svalbard, 1985

By the end of the 1950s, vehicle transportation had become more ubiquitous. The Mapping

Authority acquired a number of Volvo Duett cars from 1957 to 1969. This period also saw the

first use of helicopters as a mode of transportation in the mountains. This meant that is was no

longer necessary to set up tented camps in the mountains, while periods of good weather

could also be exploited advantageously.

9. TRANSITION TO SATELLITE GEODESY

Doppler surveying for positioning was introduced to Norway in the 1970s, and the first

practical use of GPS in Norway occurred in 1985/1986. A control network in Svalbard was

established using GPS at this time. This project was nothing short of ground-breaking.

Around 80 points were established

using Texas Instruments TI 4100

GPS receivers. In 1986, the

Norwegian Geographical Survey

changed its name to the Norwegian

Mapping Authority (Norwegian:

Statens kartverk). Over time, GPS

was adopted for most cartography

and surveying purposes, and the last

major triangulation project was

carried out in Narvik in 1990. Since

1991, all geodetic control points have

been established by means of satellite

geodesy. During the 1990s, the

Mapping Authority began setting up

permanent GNSS stations. Today, there are more than 200 of these stations and the use of

positioning services has become the most common surveying method.

Figure 17. Triangulation with helicopter transport in the 1970s

10. A NEW GEODETIC REFERENCE FRAME

It became apparent early on that NGO1948 comprised sizeable distortions. One of the reasons

for this is that calculation of the network had to be performed in blocks, using the calculation

methods available at that time. Distance measurements were carried out in the first-order

network over many years. This was done to improve the network in order to establish a new

national reference frame. But satellite geodesy had changed the world, and it was realized in

the early 1990s that a national frame of reference based on angle and distance measurements

was inadequate to satisfy future accuracy requirements. For the second time within a hundred

years, the Norwegian Mapping Authority decided to – once more – measure the entire

country, this time with GPS. In 1993 the decision was made to adopt ETRF89 as the new

reference frame, and work on establishing the high-order control network got underway. By

2008, after 15 years of effort, approximately 12,000 points had been determined using static

GPS. By 2009, all municipalities in the country had adopted ETRF89, while NGO1948 had

been assigned to the annals of history.

11. ELEVATION MEASUREMENT

In 1826, the Mapping Authority began measuring elevations using mercury barometers. And,

from 1846, vertical angle measurements were also used in conjunction with triangulation.

Older instruments were modified in order to be used for this purpose. Interest began to

develop in the height of mountaintops and, in the 1840s, it was estimated that Galdhøpiggen

was most likely Norway's tallest mountain.

In the 1870s, contour lines began being

used on maps to denote elevation. By this

time, several European countries had

begun establishing height datums by

means of precise levelling. The Mapping

Authority commenced with the

establishment of a national levelling

network in 1887. The work progressed

very slowly, and it took 25 years to

establish 887 km of levelling lines in

Eastern Norway.

Only in 1916 did precise levelling

commence in earnest. New equipment was

acquired and accuracy was drastically

improved. A new national height datum,

NN1954, was calculated in 1956, based on

8,468 km of precision levelling. Levelling

performed prior to 1916 was not used due

to inferior accuracy.

Norway is now in the process of adopting

the NN2000 height system. This system is

based on 30,000 km of precise levelling

measured over the course of 100 years. For

this reason, 1916 is considered the

beginning of modern precision levelling in

Norway.

Figure 19 Precise levelling in the 1920s

12. CLOSING REMARKS

After successive development of the triangulation measurement method spanning more than

200 years, satellite geodesy has completely transformed the discipline. Today, we have

permanent GNSS stations which gather data continuously. Positioning systems make land

surveying infinitely simpler, and we achieve a degree of accuracy that our predecessors would

never have dreamed of. It is no longer necessary to haul heavy equipment out into the field or

stay in tents for weeks on end in poor weather. The efforts of our predecessors to establish a

geodetic control network in Norway and other countries are hugely impressive. And the work

involved in surveying and mapping has produced untold benefits for society and societal

development.

REFERENCES

Gleditsch, K. (1964): Dyrhaugstind, from the annual publication of the Norwegian Trekking

Association

Harsson, B. G. and Aanrud, R. (2016): Med kart skal landet bygges – The complete history of

the Norwegian Mapping Authority from 1773 to 2016. ISBN 978-82-7945-471-7

BIOGRAPHICAL NOTES

Per Chr. Bratheim is head of the Geodetic Infrastructure section of the Norwegian Mapping

Authority. He is member of the Struve Geodetic Arc Coordinating Committee.

Bjørn Geirr Harsson worked as a geodesist in the Geodesy Division at the Norwegian

Mapping Authority from 1968 until he retired in 2005. He has published a large number of

geodetic articles and held a number of positions in Norwegian as well as international

geodetic organizations. He participated in the international group that worked for the

inclusion of the Struve Geodetic Arc in UNESCO's List of World Heritage sites. In 2016, he

published a book "Med kart skal landet bygges" about the history of surveying and mapping

in Norway.

CONTACTS

Per Chr. Bratheim

Head of Section

Geodetic Institute

Section Geodetic Infrastructure

E-mail: per.christian.bratheim@kartverket.no

Ph: +47 32 11 81 21

www.kartverket.no