Dienstag, 26. August 2014

Mappers blog: Gemsfairen - 31 years of orienteering mapping

Last weekend the Swiss Long Champs were held on the balcony of Gemsfairen. The terrain is alpine and pretty remote and therefore seldom used. The last orienteering map over the terrain was produced in 1983 as it was planed to hold the Swiss Champs 1984 on it, but the latter had to be cancelled because of snow. The year after a national competition was held in compensation (no snow then, but ice cold rain :-P). I put on the corresponding excerpts of the 1983 (src: OL KTV Altdorf) and the 2014 (src:Daniel Hubmann) map of the location Tüfels fridhof (Devils cemetery).
There are many interesting points to see in this comparison both in regard to the production of the map (Laser, professional mappers, OCAD) as to the maps content (new mapping norm, lowered level of generalization and legibility, surge of form lines) maybe even in regard of course setting?


Anonym hat gesagt…

I think the basemap was very similar for both maps: photogrammetry 30 years ago, stereo auto correlation from aerial images now (no lidar data!).
Hubert Klauser

M.Lerjen hat gesagt…

You are right in the point, that the DEM for this area (above 2000m a.s.l.) is not based on LIDAR but stereo auto correlation (SwissAlti3D).
Though there are are still significant differences between the 1983 basemap produced by Bakken & Helgesen and a digital DEM. I want to do and come back later.
Best regards

M.Lerjen hat gesagt…

Here a link to an article from Gian-Reto Schaad about the base material Steiner and Imhof had. The base material was thus partly laser, partly stereo-correlation.