[Tagging] Mapping deforestation wikipage

Lorenzo Stucchi lorenzostucchi95 at outlook.it
Sat Mar 16 08:07:18 UTC 2019


The idea is for sure to check the date of the imagery and map when new imagery are available and we can consider also the time step between the different satellite imagery.

The fact that some contributor modify the data is not a problem because they will done adding new information and this is just an improvement in the data.

Think like they are highway, I can’t known what is the type of the highway but I can cleary see that its a road, so I can map it as highway=road with all the problem of this case. But un other user with better knowledge can identify which type of highway.
In a similar way there is just a different structure of classification, and when better imagery or generally better info are available the tag landcover will be improved with the more detailed tag.

For what regards the history I’m agree with Martin.


Il giorno 15 mar 2019, alle ore 08:32, Joseph Eisenberg <joseph.eisenberg at gmail.com<mailto:joseph.eisenberg at gmail.com>> ha scritto:

> “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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