let’s have a short summary of our meeting yesterday in Chiang Mai.
While there are multiple issues observed with the way data is mapped by Facebook (like number of nodes on ways not justified with the geometry, e.g., sometimes too few, other times too many), there are issues with the tagging of roads like potentially tagging driveways as residential or agricultural tracks as residential. Or unconnected highways where different imagery could have indicated a connection. Also sometimes trusting too much the positional accuracy of the imagery layer without cross-checking the alignment to GPS tracks.
The most annoying problem had been identified as agricultural tracks being classified as unclassified (or residential), providing routing software a good alternative to the proper roads by saving a few meters of distance. This also happens in case of a missed turn when the routing tries to bring you back on track and suggests to cross through some fields to U-turn.
As we have no good statistic about how frequent these problems really are, we decided to largely extend the changeset comments on discovered problems instead of reporting the issues in private messages or simply fixing them.
We also agreed that once a way was verified by a community member on the ground we are removing the import=yes tagging on the element.
We are also going to cross-check a random sample of these highways to get some numbers regarding how frequent such problems are. I will provide some tolling for this.
I will also provide a style for JOSM to highlight Facebook roads.
For checking changeset discussions, see here an overview of the last comments for Thailand:
http://resultmaps.neis-one.org/osm-discussions?c=Thailand&d=30#7/15.117/101.649
To get all discussions involving a specific user, go to
http://hdyc.neis-one.org/
and search for the username. Click on the link to view the commented discussions, then remove the “&commented” part from the URL. Maybe someone knows a more direct way to come there by knowing only the username and not id.
It was also asked how to see where a specific user has edited. The hdyc site from above can give some hints already. For details, you could search in the data, see here for an example: https://overpass-turbo.eu/s/CGY
To visualize changes, have a look at this: https://overpass-api.de/achavi/