[Geographiclib-users] Projecting ECEF into UTM

[Ben A. <ad...@in...>]

Hello GeographicLib,

I'm rather new to geodesy and trying to project ECEF/geocentric 
coordinates into UTMUPS/WGS84 with the height given relative to the 
WGS84 ellipsoid. And I have a few questions:

1) For a given set of ECEF coordinates, I first need to get the 
corresponding UTM zone's central meridian and description. This might 
sound trivial at first, but then there's Norway and all the other 
exceptions close to the north pole. And there's UPS for the poles.

  a) How can I do this with GeographicLib? Which classes/methods should 
I use?

  b) How can I get the WKT or EPSG code for the chosen UTM/UPS zone?

2) Looking at GeographicLib::TransverseMercatorExact, it seems I must 
input lat/lon in order to retrieve the desired UTM coordinates. This 
means I must first convert ECEF into geodetic, which is also handled by 
GeographicLib. But,

  a) do I need to input geodetic or geocentric latitude?

  b) The docs say "The latitude of origin is taken to be the equator". 
While true for northern zones, Does that mean I need to introduce a 
false northing (of -10M meters) in southern zones when using GeographicLib?

  c) can I just re-use the geodetic WGS84 height as UTM height without 
conversion? I think so, but I have erred often in the past :)

I'm not sure whether GeographicLib is suited to my needs, or whether I 
should use another lib for this, e.g. PROJ.4. Any hints on this?

thanks!
ben