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Norwegian Mapping Authority

The Norwegian Mapping Authority's transformation libraries (Windows dll files), for transforming coordinates between Norway's three geodetic datums NGO1948, ED50 and EUREF89, can be ordered from the Norwegian Mapping Authority's websites. The program will eventually be phased out with the new transformation library PROJ when the Norwegian Mapping Authority's new transformation service meets all customer needs.

The national formula, Skt2lan1.dll, is the nationwide transformation library. The national formula contains all functionality and can be used for most purposes. There are also county and municipal transformation libraries for transformation between EUREF89 and NGO1948. These libraries do not have all the functions found in the national formula.

Note

The library for converting coordinates within the same reference frame, i.e., between EUREF and NTM, comes with the Gemini Terrain installation and can be used freely.

The Norwegian Mapping Authority also publishes height reference models for converting between ellipsoidal heights and heights in the national height systems NN1954 and NN2000.

NNTrans2013a.bin (October 28, 2013) contains delta heights and can be used when transforming data between NN1954 to NN2000 (standard direction is from NN54 to NN2000). Alternatively, you can transform between height systems using height reference models (geoid models).

Warning

The program requires that the Norwegian Mapping Authority's transformation libraries are located in the Exe folder of the program. You must keep track of having the latest updated files from the Norwegian Mapping Authority yourself.

Creating Transformations

How to define a new transformation with the Norwegian Mapping Authority's transformation library in plan?

Procedure

  1. Open Gemini Terrain Settings - Project - General and click on Plan Transformations...
  2. Click New... and select transformation type Norwegian Mapping Authority
  3. Define the transformation and click Save
  4. Check that the transformation is added to the list and click Close

How to define a new transformation with the Norwegian Mapping Authority's geoid model with delta heights?

Procedure

  1. Open the Gemini Terrain Settings - Project - General dialog and click on Height Transformations...
  2. Click New... and select transformation type Height Transformation: Norwegian Mapping Authority
  3. Define the transformation and click Save
  4. Check that the transformation is added to the list and click Close

Standard application layers and surveying application layers contain information about reference systems and can be transformed directly.

For standard application layers, you can also transform data during import and export.

Using Transformations

How to transform between two coordinate systems or height systems during import?

Procedure

  1. Select Import... in the application layer dialog
  2. Click Add file(s), select the file and click Open
  3. Click Import and answer Yes to select transformation
  4. Select transformation in the list and click OK

How to transform between two coordinate systems or height systems during export?

Procedure

  1. Select Export... in the application layer dialog
  2. Select Coordinate System or Height System you want to transform to
  3. Click Browse..., name the output file and click Open
  4. Click Export
  5. Select transformation in the list and click OK

Possible Error Codes During Transformation

Error Number Cause
1 KORR->Z
5 Error in to/from index
10 X too large
18 Too few, or outside the area of specified extrapolation points
19 X or Y value outside area
21 Wrong position
34 Wrong axis
35 Error in input data / Wrong From-sys or To-sys
36 Error in input data
38 Error in input data
41 Wrong NGO axis
42 Wrong UTM zone
43 X outside Norway
51 Error in to/from index
52 Wrong ellipse index
53 Wrong isometric latitude
54 Error in BRQ, neg. isometric latitude
61 Error regarding semi-major axis
62 Error regarding flattening
63 Wrong latitude
64 Wrong longitude
70 / 270 Error reading geoid information
71 / 271 Outside coverage of geoid file
73 / 273 Geoid file does not contain correct information
75 Error opening common point file
81 Wrong latitude
82 Wrong longitude
90 Outside area
91 Wrong X coordinate
92 Wrong Y coordinate
93 Wrong Z coordinate
94 Outside area
95 Error in system number (1-6)
106 From routine gdec when geoid file is not initiated
306 From routine GeoTrans when geoid file is not initiated