Opened 17 years ago
Last modified 13 years ago
#2221 closed defect
Bad 'angle follow' case -- possibly a use for splining — at Version 1
Reported by: | crschmidt | Owned by: | sdlime |
---|---|---|---|
Priority: | high | Milestone: | 6.0 release |
Component: | MapServer C Library | Version: | svn-trunk (development) |
Severity: | normal | Keywords: | |
Cc: | aboudreault, dmorissette, tbonfort, woodbri, jmckenna |
Description (last modified by )
http://boston.freemap.in/bugs/2221/poor_follow.png Uses:
http://boston.freemap.in/bugs/2221/poor-follow.map
All data in:
http://boston.freemap.in/bugs/2221/
Command used:
shp2img -m poor-follow.map -o poor_follow.png -e 232376.94043 900487.441406 232524.42627 900634.927246 -l roads_3_1
Discussion on IRC:
20:24:28 < hobu> Someone needs to do some splining 20:24:29 < crschmidt> Should I bother to file it as a bug? 20:25:06 < hobu> You could file an enhancement for 5.2 that says, 'we should improve ANGLE FOLLOW to support simple interpolation methods like splining for degenerative cases" 20:25:24 < hobu> It's way too big to be dealt with in the throws of our 5.0 release right now though 20:25:40 < crschmidt> understood 20:25:46 < crschmidt> Just wasn't sure if it was worth filing at all 20:26:19 < hobu> Another thing about the splining is we could maybe take advantage of it for feature rendering as well 20:26:38 < hobu> something those paleogeographers do from time to time ;) <crschmidt> what is that? <crschmidt> straightening out of too-curvy borders? <hobu> smoothen disjointed ones. They add map noise for very little information * crschmidt nods <crschmidt> something like what a simplification algorithm would do <crschmidt> only automatic/built into the rendering? <hobu> right, except not one that has to preserve topological relationships <hobu> http://en.wikipedia.org/wiki/B-spline <hobu> Would be a simple approach <hobu> Maybe you'd tell the mapserver renderer, 'hey, use 6-8 consequtive vertices to calculate your splines, if the incident angle is less than x degrees" <hobu> or something like that ;) <hobu> It'd be spendy, for sure <hobu> and not very useful for Manhattan grid systems :)
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