Geoscience Reference
In-Depth Information
Fig. 10
The northern end of Picard's and Cassini's baseline is marked and commemorated by
an obelisk at Villejuif, standing in a suburban garden, with trees newly planted nearby to mark
the Méridienne Verte. (Photo by the author)
intervisibility (it would be disappointing to climb to the top of a mountain with loads
of equipment and find that there was a peak in the way of the line of sight to one of
the other landmarks). Typically, the landmarks alternate from one side of the meridian
to the other so that when candidate landmarks are identified their position was
roughly estimated. In this way Picard drew up his network of triangulation stations.
After choosing the trig points, Picard or his colleagues made many measure-
ments from each station and documented the features to be transcribed on to the
