[OSRS-PROJ] Roussilhe Oblique Stereographic

Gerald Evenden gerald.evenden at verizon.net
Tue Mar 16 15:19:50 EST 2004

As an aside to the discussion about the Roussilhe Stereographics there
are already two stereographics in libproj4: 1) Snyder's that uses the
simplified conformal latitude expresion (+proj=stere) and 2) a version
that used the full feature conformal latitude expression (+proj=sterea).

Using libproj4's internal verbosity procedures (-V) the later method
is slight more accurate in terms of scale error.

The "full feature" conformal latitude routine is also used in the
Krovak and Swiss projections.  Note that both versions of the
Roussilhe versions use the simplified conformal procedure.

You see that with all these damn details why I do not want to become
involved with datum processes.  Another interesting detail is that
Frederick Pearson, II is the only current author I can find that deals
with the full version of the conformal conversion and even he discards
the integration constant that is computed in the libproj4 software.
As I recall, Snyder did not have a kind opinion of Pearson but I've
forgotten why.

Aren't projections fun?
Jerry and the low riders: Daisy Mae and Joshua

PROJ.4 Discussion List
See http://www.remotesensing.org/proj for subscription, unsubscription
and other information.

More information about the Proj mailing list