Error categories

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This page contains a list of typical geometric errors, how you can find those errors and how to correct them.


Picture Category Problem How to find How to correct
Wrong offset ru2.jpg Use of satellite images without offset correction. Roads are offset away from tracks Manually - download map and GPS data Shift imagery until tracks will be matched.) Use an area with a high number of tracks for average things out, and spot GPS traces which had a bad fix. Then place objects according to the shifted imagery.
Unconnected highway (touching) This is a severe error when looking at routing applications. Connected roads are not connected in OSM data. WayCheck by gary68 Connect nodes in JOSM with merge function
Unconnected highway (open) This may be a severe error when looking at routing applications. Is the highway really just ending there? WayCheck by gary68 Connect nodes in JOSM with merge function. Or extend map.
Potlatch Josm
Crossroads unconected potlach.png Crossroads unconected potlach2.png Crossroads unconected josm1.png Crossroads unconected josm2.png
Potlatch (node marked by a circle) Josm (the increased square)
Crossroads conected potlach.png Crossroads conected josm1.png
Crossing on same layer without common node Either bridge or tunnel and layer is missing or a common node is missing. Either reality is not reflected correctly or routing cannot be done correctly because roads are not connected in data. Add layer information and bridge/tunnel information. Or create common node:
Err04.png Open areas Reality is not reflected correctly and maybe some programs might have problems using those polygons. by gary68 Close areas by prolonging the way. Last node has to be the same as the first.
Err05.png Oneway errors on motorways Imaging you are sitting in a car navigated by OSM using this data... MotorwayCheck by gary68 Correct tagging and/or direction of way. Josm reverse way i.e.
Doubled nodes in ways by gary68 good question...
Err06.png Roundabouts with wrong direction by gary68 Reverse way with i.e. Josm or add oneway=-1 tag.

See also