We know from experience that the answer is "very expensive". We had a
large number of "init=epsg:" references in a mapfile and when we
converted them to straight proj4 strings realized almost a second in
speed improvements.
Frank Warmerdam wrote:
Ed McNierney wrote:
I have not found that unnecessary projection definitions are expensive,
but I certainly agree that minimalist mapfiles will save you a lot of
time.
Ed, others,
I think a projection block that provides all the parameters should be very
"cheap" in processing time, but any time you refer to projection details by
EPSG code number, there is a whole file lookup involved. As far as I know
cost is paid for each EPSG reference, even if many places refer to the same
code. I would definately like to make some improvements in this regard,
likely within PROJ itself.
It would be interesting to prepare some timetests on this issue to see just
how significant it is.
Best regards,
