> > > “The idea is to have mapathon in > > different time, when new imagery are > > available and after check what > > changed searching in the database >
In this case you only need to map the area of woodland or forest now, and it’s no problem to leave other landuse and natural areas unmapped. But it may be difficult to use the OSM database for checking changes over time, if you would like scientific, publishable results. To properly compare the current woodland area with the area in a couple of years, you will need to make sure that the aerial imagery that you use now is all from the same year. Then, when you repeat the project in 1 or 2 years, you need to have new imagery from around the same time, and you should map the woodland or forested areas using the same standard and methods as they first time. This will be easiest if you remap everything from scratch the second time as well. If you try to use the OSM database both times, you may find that other mappers have changed things in the meantime. Perhaps they have changed some of your landuse=forest to natural=wetland wetland=mangrove, because they know the area better. Perhaps they have mapped a new palm oil plantation based on local information, but it isn’t visible in the aerial imagery. How will you deal with such changes? So it is great to add the forest or wood areas to OSM right now based on the latest aerial imager. But you should plan to keep your own copy of the database to compare with and edit in the future. If you do this right it could be professionally-quality data for environmental research, but that means you need to keep a copy of the data that won’t change, and use that for comparison in the future.
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