As part of the Japan road improvement series, OSM Japan community has successfully completed the mega Tokyo task of re-aligning the major roads with the orthorectified GSI imagery.
Data improvement in urban areas like Tokyo presents its unique challenges. Quite notable here is the data density. Since JOSM editor has an upper limit on the number of objects that could be fetched in a single download, every task area had to be split further into smaller ones. There were instances, particularly in inner city areas, where a single task was broken to 16 smaller ones! But this was never a deterrent for the 31 enthusiastic mappers who toiled over two weeks to complete the enormous task 🙌
Next in the pipeline is road improvement in Nagoya city.
Nagoya being an urban area like Tokyo, is well mapped and the data density is huge. And the objective here remains the same as the Tokyo mega task.
- Realign and merge major highways (motorway, trunk, primary and secondary)
- Create dual carriageways on major highways with link roads and correct oneways
Do visit the task page on teachosm, http://tasks.teachosm.org/project/104 for instructions on how to go about the task.
Also you can get more details on data issues in Japan, from earlier diary entries of PlaneMad and pratikyadav. Japanese tranlsations are available in MAPconcierge’s diary entries, here and here.