[OSRS-PROJ] Pseudo X/Y values, forward and reverse

Gerald I. Evenden gerald.evenden at verizon.net
Fri Jan 31 20:27:48 EST 2003

The most suitable solution to your problem is finding the proper
projection for you application rather than trying to bend existing
systems that are not suitable.  If your lines are parallel to parallels
then Lambert Conformal Conic would be suitable, and in NS then
TM would work well.  But it sounds like they are probably oblique
and thus Oblique Mercator would be the best projection.

This assumes that a conformal projection is most suitable for
your needs.  In the case of OM you need to determine the best
geodesic that fits your line and use this for the OM factors.
Scale error will be at a minimum all along your seismic line.

As others have pointed out, appropriate selection of projection to
fit the needs of a project is a most important decision and one
should not be overly influenced by exiting projections that have
entirely different requirements.

On Fri, 2003-01-31 at 17:12, William Hersman wrote:
> Yes, let me explain a bit.  I am not a geodicist, so bear with me, I'm a
> computer programmer.  We have a situation here where we need to do regional
> analysis that expands across a major portion of Alaska.  There are seismic
> lines which are very long, extending for hundreds of miles.  The analysis
> will involve seismic data from the Canadian border well out to the Chukchi
> Sea.  The software used for this analysis requires that one, and only one
> projection be used for the entire project.  All of the data must be loaded
> in that one projection.  It has been traditional in our work to use either
> UTM or Alaska State Plane as a preferred projection.  Yes, one could argue
> that there are better projections to use, I would not diagree, but it has
> been decided for better or worse to go with Stateplane.
> This requires that all lat/long values which are currently carried with the

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