sommerluk
commented
6 years ago Hello Andrew.
Nice to hear from you. That sound’s great!
Some points that I could comment as a local community member:
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You have mentioned “Highway tags Africa”. That’s good: Indeed we stick to “Highway tags Africa” – means: The “highway” tag is chosen following the importance of the road for the road network, and not following the current maintenance state of the road.
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It is important to have the “surface” key (at least with the raw distinction between “paved” and ”unpaved”). As the ”highway” tag does not say much about the actual conditions, there can be a big difference between a secondary road that is paved and a secondary roads that’s unpaved. This information is really important to calculate the time it takes to use a certain road. The “surface” key is therefore as important as the “highway” key itself.
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For motorway, trunk and primary, I think there are (practically) no missing roads in Ivory Coast. The tracing quality however varies. Around Abidjan, the tracing is in general quite good. But as further you go away from Abidjan, more often you might find “highway=*” geometries that have very long distances between two nodes. Improving the accuracy here would be great.
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For “highway=secondary” and lower, you might also find roads that are missing at all in OSM. The lower the road type, the more roads are missing.
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The most widespread road tagging error in Ivory Coast is likely tagging of normal unpaved roads as “highway=track”. “highway=track” should be used only for forestry and agricultural use, but currently it is often miss-used for unpaved roads in general (as it renders in brown in the standard style). This could be fixed by using an appropriate “highway” value (often “unclassified”) together with “surface=unpaved”.
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A particular problem might be roads that are crossing rivers. Sometimes the two OSM geometries are simply crossing, and on the satellite image you can see a bridge: Here you could fix the tagging by applying “bridge=yes” and “layer=1” to the considered part of the road (and maybe the outline of the bridge with “man_made=bridge” + “layer=1”). But sometimes there might be no bridge on the ground – only a ferry connection – and the current OSM data is simply wrong.
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Don’t worry about roads that have no names in OSM. Almost all roads in Ivory Coast do not have a name on the ground!
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Satellite image quality varies. It is worth to try various satellite images for the same place, there are often differences. In Abidjan, Esri seems to be more up-to-date (about 2018, while the other image layers are about 2015) than the other image layers. Not sure about the rest of Ivory Coast. DigitalGlobe has a quite complete high-zoom coverage for Ivory Coast (but maybe older than Esri).
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There is a considerable number of roads that are badly aligned. Probably because the first contributors did not have GPS traces to align the satellite images. Fixing this would be great.
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We have much more GPS traces than before, but still not everywhere. More GPS traces in the bigger cities. Strava can help also – at least in Abidjan, it covers some locations that are not covered by GPS traces.
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Mapillary and Openstreetcam has images for Ivory Coast – mostly in Abidjan.
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The region where is most construction work going on is around Abidjan: Not in the centre of Abidjan, but in the outskirts, and also in the villages in a diameter of 50 or 100 km around Abidjan.
Thanks for contributing in Ivory Coast. You’re welcome!
If you need some more help, let me know!
Best regards
Lukas Sommer
awisemanapple
Task Description
This task outlines work to improve map data in Côte d'Ivoire. We plan to work on improving the road network, such as adding missing roads, fixing network issues such as missing connections or crossing roads, and other related issues. We also plan to update and correct coastline and water features as we find them, and correct and improve land use and land cover polygons where needed, such as airports, national parks, forests, colleges and universities, and so on -- remove duplicates, correct the boundaries, fix incorrect tags and other similar things.
Improvements that will be addressed include the following:
Mapping Guidelines
The team will follow OSM and local policy, along with any other guidelines as appropriate. We have also messaged talk-CI to get feedback and suggestions about the project.
For water and coastlines, the team will follow OSM coastline guidelines, waterways policy such as water and natural=water and local policy along with any other policy as appropriate. Some coastlines are connected to administrative boundaries, in which case we will adjust both if appropriate Where we see them, we will remove the
source=PGStag, which was from an earlier coastline import that needs to be cleaned up. We received a message on the India coastlines project requesting this, and it is commonly done in other coastline improvement edits.The team will use the imagery and data sources specified below as needed for mapping in the country.
When in doubt, the team will use the existing tags and data which are used locally. The history in JOSM (ctrl-H) identifies what previous mappers added and their notes and/or explanations regarding changes made. This history can also show if a previous mapper has visited that area or has expert knowledge or sources.
We have also messaged talk-ci to get feedback and suggestions about the project.
Our team uses the hashtag #adt (for Apple Data Team) for our edits.
Area of Focus
Throughout Cote d'Ivoire (Ivory Coast).
Tools
The team will use JOSM for completing the task. JOSM has validation warnings for road networks and other possible issues that are important to prevent improper changes.
Sources
The team will apply image offsets as needed.
Changeset Comments
The team will provide changeset comments that are in compliance with OSM changeset guidelines.
Error Detection
The team will check for errors visually and using JOSM validation warnings prior to committing the changeset.
In addition, the team will review its work in accordance with validation guidelines such as the OSM Wiki and LearnOSM validation guidelines
Things you can do
If you'd like to help, here are a few ideas:
Contributors
MapRoulette
We have also posted MapRoulette challenges related to the road network: https://maproulette.org/browse/projects/40664
For more information
Our community lead is Teddy Ahlvin and our editing leads are Jon Westlake and Erica Olson. To get in touch with Teddy, you can email or contact him via OSM. All of our leads can be reached via email.
OSM Wiki