Hi Alexander,
On Mon, Jul 7, 2014 at 1:09 PM, Alexander W. Janssen < [email protected]> wrote: > On Mon, Jul 7, 2014 at 10:43 AM, Dan S <[email protected]> wrote: > > Hi Alex, > > Hi Dan! > > > 1) Yes, sometimes it's frustratingly difficult with low-res imagery to > > know what you can contribute. I would say DEFINITELY carry on mapping > > those big waterways you mention. In my experience, when we're trying > > to map an unmapped area, having those landmarks in OSM's database > > (waterways, major roads, residential areas) really helps future > > mappers to have points of reference, even if they are approximate and > > need refining later. > > OK, will continue with that. > > > 2) Re farmlands and forests: I sometimes draw these in, but not often. > > I agree with you that it seems helpful to give a rough picture of the > > landscape to expect, BUT on the other hand, I think having these > > polygons all over can sometimes make the more important jobs harder: > > jobs such as checking that every single building has been captured. > > And since these landuse polygons are pretty much never requested in > > the tasks (apart from landuse=residential which is often a crucial > > first step), it seems the locals and the aid organisations don't > > particularly need them. So I would suggest don't spend much time on > > those. > > Ah, allright. Well, I prioritize anyway; if I'm in the mood I'll just > draw it anyway :-) > I would say it depends on the situation. Eg in Khartoum ( http://www.openstreetmap.org/#map=12/15.7493/32.5389) I found interesting to add the residential areas as well as the brownfields and farmlands around or inside. Brown-fields and farmlands rather than something left blank also say we did not miss a residential area. In Central African Republic, basically the residential areas are surrounded by farmlands then forest. Would be interesting to add the cultivated areas, but maybe through a remote sensing analysis as the extent will vary from a year to another and do not need to be extremely precise. > > > If you see tasks which seem fairly complete, it > > might be a better use of your time to get yourself to a point where > > you feel confident enough to *validate* other people's completed > > squares. It takes a little while to feel confident about being a > > validator but we always need more validation effort than we get. > > Good point; however, when it comes to the validating part, I know how > hard that is in my area - especially when it comes to correct road > relations and the such. There are still many grey areas, as soon as we > run out of unaddressed areas, I'll look other the validation part. So > that more skilled people can concentrate on that first. Also, Is there > a feedback process in case I'm doing something wrong? I guess if I > make a mistake, I'll do the same over and over again. Got the wiki in > another tab open for reference at all times, but well, you know how it > is. > > > 3) Firstly, you should indeed tag the changeset with the actual > > imagery you used. > > I thought so. > > > But secondly, if you're not careful about which > > imagery you use, there's a risk that you might end up tracing from > > imagery that is a couple of years old or something like that. > > Luckily Bing shows a date in JOSM and all of it shows 2014 up until now. > > > My personal approach would be to try and use the recommended imagery, > > since someone has usually put effort in to working out which imagery > > is most appropriate. Also, there's usually a conversation on the > > mailing list which always gives some clues about what to use. > > I paid attention to this, however other people seem to have the same > problem - MapBox/Digital Globe is not exactly high-res. In one > occasion I could use Spot data, but that seems to be rare. > > I wonder if it'd be useful to use Sentinel 1-A data? It's free to use > and available at ESA's Sentinel Data Hub. However, the 1-A satellite > was just recently comissioned and the webinterface is a nightmare. > Also, the data products aren't really curated yet, only level-1 > products are really useful now and we're speaking about TIFF-blobs > hundreds of Megabytes large. I think these would've to be split to > tiles and zoom-levels first before they're really useful to JOSM. > > Information about ESA's Sentinel project: > https://sentinel.esa.int/web/sentinel/home > Sentinel Data hub: https://senthub.esa.int/ > > Regristration and usage is free. > > > Dan > > Alex. > > > -- > The best thing about procrastinating is you can do it NOW and ANYTIME. > > _______________________________________________ > HOT mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/hot >
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