Vikings and mapping methods.
By measuring the height of the sun at noon and eykt over the year and the amplitude (sunrise and sunset) at the same latitude following a given meridian, the Vikings were able to make a gnomonic projection and a mapping of the area where they were travelling.
On the bearingdial at left an interesting part of the map shows Cape Breton at 46N, which will be near eykt at skamdag (wintersolstice). Eykt-measurement was a method the Vikings were using as mentioned by Leif Eriksson when he visited Vinland at 1000AD.
It was "eyktarstadr" (sunset) in a special daymark (eykt) at "skamdagr" (winter solstice). The map is showing this latitude around 48N (modern astronomically calculations 48.16N) or 49.23 N using Viking method calculating sunrise. The Gnomon (edge on the bearingdial at left) is cut on this latitude
"Eykt" means 1/8 of the horizon in daytime. The Vikings used it as a daymark (based on the amplitude) from noon where the sun were directed towards South and the shadow from the gnomon were directed towards North. It is a fixpoint in the horizon.
The image belowe is a subset of the map on the bearingdial showing Cape Breton and directions towards St. Pierre and Miquelon at Newfoundland. The map is true on distances compared with modern maps (Mercator), but may not be mistaked with the directions from a magnetic compass.
Updated 16. sept. 2005
Copyright 2005 Erik Torpegaard