PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
July 2017
473
Nordlaguna Datum of 1949 origin where: Φ
o
= 71° 00´ 46.79˝
North, Λ
o
= 08° 27´ 51.3˝ West of Greenwich. The local Nordla-
guna Grid is based on the Datum origin with a Gauss-Krüger
Transverse Mercator where the scale factor at origin, mo =
1.0, the central meridian (C. M.),
l
o
= 08° 30´ West of Green-
wich, the False Easting (Y axis) at C. M. = 50 kilometers, and
the False Northing (X-axis) = 7,800 kilometers. Note that the
transposition of the axes labels is common in Europe.
In January of 1986, all mapping activities in the Kingdom
were consolidated under the new banner of Staatens Kartverk
(Norwegian Map-ping Authority) in Hønefoss. By 1990, the con-
cern for establishing a coordinate system that was consistent
for European offshore hydrocarbon exploitation resulted in the
“North Sea Formulae.” The published parameters to shift from
ED50 to ED87 are 4
th
degree 15-coefficient multiple regression
equations. The published parameters for transforming from the
“new” European Datum of 1987 to the World Geodetic System
of 1984 Da-tum has a specific subset of relations referred to as
the “WGS84*SEA.” The parameters are:
Δ
X = –82.981m,
Δ
Y =
–99.719m,
Δ
Z = –110.709m, R
x
= –0.5076, R
y
= +0.1503, R
z
=
+0.3898, scale = –0.3143 where the rotations are in micro radi-
ans and the scale factor is in parts per million (10
-6
). For exam-
ple; from ED87 coordinates: N = 52°, 8 = 02°; the WGS84*SEA
co-ordinates are: N = 51° 59´ 57.0927˝, and 8 = 01° 59´ 55.1400˝.
The number of each country’s terrestrial points used in the
solution was based on a proportion of comparative North Sea
coastline lengths. This transformation system was a consensus
of agreement among Norway (26), United Kingdom (43), Den-
mark (12), Germany (9), and the Netherlands (13).
A transformation algorithmwas developed by the Norwegians
to go between the NGO1948 Datum and the ED50. This series
of transformations were developed as “block” transformations
based on specific areas. All of the 2D shifts are on the conformal
plane of the UTMGrid, which was the rationale used by the US-
C&GS (on contract to AMS) to compute and adjust the North-
ern Block of the ED50. With 12 different blocks de-fined for the
Scandinavian Peninsula, the implementation is non-trivial.
The Norwegian government is commercially marketing a da-
tum shift solution similar to the Canadians and the British. A
software pack-age is available (for a price) that will implement
coordinate transformations based on the EUREF89 Datum. The
package is called “WSKTRANS,” and it works on two levels. On
the national level, the formula is based on approximately 500 of
the old first-and second-order triangulation stations. The accu-
racy is guaranteed to within 1 meter. On the county level, a net-
work of GPS stations called “Landsnett” has been observed at a
5-km spacing such that the formula used in WSKTRANS has
a positional transformation accuracy of about 2-cm. The Nor-
wegians now tout their Stamnett 1997 system, which is a final
adjustment of 930 stations distributed throughout the country
on the EUREF89 Datum. The Stamnett is roughly equivalent
to the HARN system for North America, and it is the basic
framework used to establish the Landsnett. No information is
avail-able on what Geoid model is used with the WSKTRANS
package, nor on whether the package is a 2D or a 3D solution.
U
pdate
Whether you are a professional developer or a “regular” user,
the Norwegian Mapping Authority site provides you with in-
formation on how to download and use their open and free
maps and geospatial data.
The following data sets from the Norwegian Mapping Au-
thority are available as free downloads:
•
Topographical land data from 1:50 000 – 1:5,000,000
(N50, N250, N500, N1000, N2000, and N5000 vector and
raster images)
•
Administrative/ property boundaries
•
Road networks including addresses
•
Place name data
•
Historical maps
•
National elevation models
To download the data sets you must register (except for histor-
ical maps). Data sets must be used according to the Norwegian
Mapping Authority’s
.
or from thei
3
(texts in Norwegian only).
We advise you to check their site, especially if you are unsure
about further procedures and the knowledge required to make
full use of their data sets.
If you are you interested in purchasing other geospatial data,
please
4
.
F
or
P
rofessionals
The map data sets are released in a form that is as close to the
original as possible. This provides professional developers with
as much free rein as possible to develop their own products and
services based on the Norwegian Mapping Authority’s data.
Topographic vector data, boundaries, road data and place
names are provided in SOSI and GeoJSON formats. The eleva-
tion models are provided as DEM’s. N50-N5000 topographical
land data can be found in ESRI File Geodatabase format, and
in addition the N50 data is available in raster format as MrSID.
At the moment, professional developers and GIS workers
will benefit the most from many of our open data sets. It is our
goal that the map data can be used to develop new solutions,
which can be useful to many users.
, June, 2017.)
The contents of this column reflect the views of the author, who is
responsible for the facts and accuracy of the data presented herein.
The contents do not necessarily reflect the official views or policies of
the American Society for Photogrammetry and Remote Sensing and/
or the Louisiana State University Center for GeoInformatics (C
4
G).
This column was previously published in
PE&RS
.
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