Richard Weait wrote: > On Sat, Mar 6, 2010 at 4:08 AM, Paul Johnson <[email protected]> wrote: >> Jonathan Bennett wrote: >> >>> No. GPS traces are just evidence, or a guide, and shouldn't be >>> interpreted literally. If they look messy, it's OK, since they're only >>> used for tracing. The amount of work needed to clean up the traces would >>> be massive (it would need to be done by hand), and we'd gain very little >>> -- it doesn't generally affect the accuracy of mapping. >> >> Surely there's an automagical way to suppress bird's nests. > > gpsbabel filters simplify and discard sort of do this, but not exactly. > > gpsbabel position filter will allow you to remove points within > $distance of a specific location, so that's good for removing a cloud > around your customary home location.
So the problem's half solved. Now we just need to figure out how to detect a ratsnest location. > I don't see a filter that both leaves 1/second points in place and > reduces clouds from stationary receivers. Upon detecting nonlinear data in a nonsensical fashion in a single track, remove superfluous data points. > Perhaps you'll be inspired by filter_skeleton.c to write an ideal > anti-birdsnest filter for gpsbabel? I would be, if it weren't for the fact I'm a civil engineering technologist, not a computer scientist. Sure, I /could/ do it, if you want to wait forever for something that would almost certainly be mistaken for unreliable crap. ;o) > Also, the imperfections of gpx track files do remind us that the track > file is not a complete survey. I'm not convinced that's a valid excuse for not doing (basic) data validation, particularly when it's been suggested and agreed upon that it could be done. _______________________________________________ newbies mailing list [email protected] http://lists.openstreetmap.org/listinfo/newbies
