[talk-au] Finding map errors

cleary osm at 97k.com
Fri Apr 14 23:29:01 UTC 2017


OSM Inspector is useful but sometimes it shows errors where none exist.
I think some "errors" might be better left alone. OSM Inspector is great
but it is not perfect.  But it is good that you have looked carefully at
the "errors" in case there were problems to be rectified.



On Fri, Apr 14, 2017, at 09:32 AM, Warin wrote:
> On 05-Apr-17 06:36 PM, Warin wrote:
> > Ok ...progress on multipolygon errors
> > These are are now down (152 file size) to mostly large things .. like 
> > relations for boundaries of the states, Australia ...
> > I don't see anything wrong with them .. other than very long ways,
> > and I think that may be the problem with these being rendered as the 
> > program maybe limited in some way.
> > OSMinspector might be reporting these as 'geometry errors'.
> >
> > I think I might try selecting one of these 'errors' and separating a 
> > reported faulty way up into smaller segments .. and see what happens,
> > if that way is also reported by OSMinspector as a long way.
> >
> Well .. tired out the long ways .. reduced them down on one relation.. 
> and they still showed up as an error .. so not long ways but something 
> else.
> The particular relation I used for testing was a one member relation - 
> changed it to a single way.
> 
> > What of the others?
> > They won't effect the display of the map too much .. but they will 
> > effect the routing.
> >
> > The ones that can be 'fixed' with armchair imagery mapping are the 
> > roundabouts.
> > Possibly barrier in NSW using the LPI base Map - that does show gates 
> > as an hourglass shape.
> >
> > There maybe some that can be fixed just using the OSM data ..
> > for instance a section of one way road that should be connected to its 
> > partner opposing one way road and isn't.
> 
> Looked at a selection of the one way errors - about 9 out of 10 are 
> entry/exits to parking areas... not interesting at all. :)
> >
> >
> > On 01-Apr-17 02:16 PM, Warin wrote:
> >> The tools for finding map errors are one way of finding some map errors.
> >> Additionally I am looking at rendering errors and gradually 'fixing' 
> >> them.
> >>
> >> As a comparison I have used the errors reported on 
> >> http://alternativaslibres.org/en/downloads.php for the UK and OZ as;
> >> these are updated daily so I can track progress.
> >> the completion between OZ and UK can be an incentive to get 'our' 
> >> errors down.
> >>
> >> Yes the UK is a smaller size, but they have a greater population, and 
> >> they therefore should have a greater number of things mapped.
> >> Anyway here it is.
> >>
> >>  File sizes in kbytes
> >>
> >> Error type         OZ file size   UK file size
> >>
> >> Turn restrictions       179            480
> >>
> >> Roundabouts         1015            130
> >>
> >> One Way roads       193            415
> >>
> >> Multiplygons           172          1,200
> >>
> >> Motorway exits        18               30
> >>
> >> House Numbers     605           5,600
> >>
> >> Flares                    173              188
> >>
> >> Barriers                   29              153
> >>
> >> Arcs                  4,000          25,000
> >>
> >> Doing well over all .. my experience with them;
> >>
> >> roundabouts are not doing well,
> >> there is a tendency to have 2 roads join the roundabout at the same 
> >> place ... and that generates an error.
> >> The separate roads should join the roundabout at different places.
> >> Tiresome to fix as it makes little difference to the map, should make 
> >> a difference to voice routing.
> >>
> >> Multipolygons have gone down from 240 to 172 so far, I have been 
> >> tackling them.
> >> Mostly ways inner and outer sharing nodes, some crossing ways.
> >> Makes a difference to map rendering.
> >>
> >> Turn restrictions .. only a few samples by me so far .. but they look 
> >> to have some members deleted.
> >> It would be handy to have names on these to say what they were .. 
> >> e.g. no right turn from Macquarie St to Bridge Rd.
> >> That would make restoration and checking much easier. I have deleted 
> >> some that never made sense. Others I have left messages for.
> >> Makes a difference to routing.
> >>
> >> One way roads .. again only a few samples.
> >> But they look to be roads that have no connection - so there must be 
> >> a large collection of vehicles at the .. or it never gets used. :)
> >> Makes a difference to routing.
> >>
> >>
> >> Barriers ... again only a few samples.
> >> These seem to be a barrier (gate) that is on more than one road ..
> >> say where 2 roads cross at right angles and the node where they cross 
> >> is a gate ... must be a strange gate :)
> >> Makes a difference to routing.
> >>
> >>
> >
> >
> 
> 
> _______________________________________________
> Talk-au mailing list
> Talk-au at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-au



More information about the Talk-au mailing list