High quality maps is critical to field work. Experienced mappers may validate existing data to fix serious errors and invalidate an area for further work.
Task Briefing
Review the work of existing mappers using the HOT Task Manager. Our priority is routing and we will focus on Road network tasks 1,2,3,6. Pick and unreviewed area and throughly examine the area for the following issues:
Incomplete/Low quality Task If there are numeruous roads missing and requires a lot more work to improve the quality, /invalidate this task/ so that others can continue to improve it. Add a comment clearly describing the reason for invalidating and what areas needs improvement.
Isolated Segments
Short segments of isolated roads or paths need to be connected to the nearest road network. Try identify missing portions in the imagery and trace them. If unsure add a FIXME=approximate alignment, needs verification tag
JOSM Validation
Run the validator ⇧+v and clear the following issues:
- Fix all errors and remove duplicates
- Node end near highway
- Crossing highway/waterway
- Ford should be on the node where Highway and waterway intersects
- Overlapping ways
- Untagged ways
- Self intersecting ways
- Incomplete Object
- Overlapping buildings
Inconsistent tagging
- Mountain trails not fit for road traffic need to be tagged as
highway=pathand nothighway=pedestrianorhighway=road - Connecting roads between habitations are usually
highway=unclassifiedand nothighway=track. If the road is not topped or looks like it is under construction use the temporaryhighway=roadtag instead
Bridges and waterway crossings
- Take special care to tag water crossings properly. Bridges must have
bridge=yes/suspension+layer=1 - If there is no bridge visible, then tag the crossing segment or intersection node with the waterway as
ford=yes
- Align your imagery if all the data is looking offset from the background
- Create a new changeset for every activity: Tracing, Realigning, Fixing: unconnected, duplicates, overlapping; Tagging: adding, correcting
- Descriptive changesets, for better conflict resolution and review. "Fixed all unconnected segments", "Fixed all overlapping ways", "Added bridge segments", "Remove duplicate ways"
- Frequent uploads, to avoid conflicts
Only validate tasks that you are confident has met the task instructions and are free of validation issues. Make sure you add a comment confirming the road network is complete and there are no validation issues. Also document any serious data issues noticed and what was fixed.
It helps to share your task number with someone else in the team for a second look, all edits are also tracked in the activity tab.
Further reading