[OSRS-PROJ] Orthographic Projections and MapServer

Gerald I. Evenden gerald.evenden at verizon.net
Thu Aug 21 17:18:55 EDT 2003

Probably senseless to reply to sarcasm.

PROJ is a part of a now defunct graphic system called MAPGEN that we
used several years ago.  It functioned fairly well for large scale
mapping and would produce accurate mylar overlays for USGS base maps.

Please note that I said "part of."  The mapping system eventually
became dated and replaced by commercial products but since my interest
was basically in the projection part I maintained and expanded the
the projection system.  Carefully note that the map drafting
system was always delivered as a two part package: MAPGEN and PROJ.
As most of you know, PROJ has applications in non-map making activities
and thus retained its usefulness in spite of the demise of the
graphic system.

To say that the PROJ system should make maps is like requiring the
same activities from sine and tangent procedures.  PROJ is only involved
in the process of transforming geographic coordinates to Cartesian so
they can be presented on a flat sheet of paper with suitable graphic
software (or even hand plotted on graph paper).

On Thu, 2003-08-21 at 16:12, Bart Adriaanse wrote:
> Gerald,
> No flames, just comments, and wishfull thinking...
> Being a typical user who knows what a projection is and how to work with
> them, but prefers to use a tool like Proj or the GIS at hand rather then
> even attempt to do my own this is mostly wishfull thinking i suppose.
> I can see clearly now there seems to be no simple solution, you opened my
> eyes to realize expecting Proj to deal with this is not realistic, i mean
> how would it anticipate on me drawing a polygon or polyline, or maybe even a
> transparent globe where points beyond the horizon show through half
> transparently ;-)
> I guess you're right...
> So my comment would boil down to simply the need to be able to find out
> which points of a polyline processed by pj_forward were over the horizon,
> from what i understand by now i could process the points one by one and
> assess the return code, right ?
> Best regards,
> Bart Adriaanse
> www.demis.nl
Gerald I. Evenden <gerald.evenden at verizon.net>

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