[alma-config]coordinates

[Simon Radford]

Not to make a big deal of this, but just a reminder:

For consistency with the maps published by the Instituto Geográphico Militar de Chile, we have prpared our maps using Universal Transverse Mercator (UTM) Zone 19 coordinates [m] and the the provisional South American 1956 datum (SAm56) datum.

In practical terms, these coordinates measure offsets in meters North and East from a reference point (far) outside our area of interest. The GPS receivers are setup for these coordinates. 

For the field survey, pad locations should be already in these coordinates. Although adding offsets, etc., may be trivial, it's not something to be done at high altitude for 250 positions. The rms uncertainty in a GPS measurement is about 3.5 m (1 sigma),
so truncation to 1 m is sufficient.

Simon

Coordinates, etc.
http://www.tuc.nrao.edu/alma/site/Chajnantor/maps/coordinates.html