I started a Mapfile Tuning HowTo on the MapServer site. It is 'public', but the effective date is set into the future, so it is only visible by hitting the URL directly.
http://mapserver.gis.umn.edu/docs/howto/mapfiletuning I didn't have time to write much this morning, once we have some real content, it I will make is visible. Add your suggestions/contributions for content as comments and I will compile them. David. -----Original Message----- From: UMN MapServer Users List [mailto:[EMAIL PROTECTED] On Behalf Of Paul Ramsey Sent: Tuesday, September 19, 2006 10:31 AM To: [email protected] Subject: Re: [UMN_MAPSERVER-USERS] Mapfile Tuning 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,
