<div dir="ltr">Hi Alexander,<br><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Jul 7, 2014 at 1:09 PM, Alexander W. Janssen <span dir="ltr"><<a href="mailto:alexander.janssen@gmail.com" target="_blank">alexander.janssen@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Mon, Jul 7, 2014 at 10:43 AM, Dan S <<a href="mailto:danstowell%2Bosm@gmail.com">danstowell+osm@gmail.com</a>> wrote:<br>
> Hi Alex,<br>
<br>
Hi Dan!<br>
<div class=""><br>
> 1) Yes, sometimes it's frustratingly difficult with low-res imagery to<br>
> know what you can contribute. I would say DEFINITELY carry on mapping<br>
> those big waterways you mention. In my experience, when we're trying<br>
> to map an unmapped area, having those landmarks in OSM's database<br>
> (waterways, major roads, residential areas) really helps future<br>
> mappers to have points of reference, even if they are approximate and<br>
> need refining later.<br>
<br>
</div>OK, will continue with that.<br>
<div class=""><br>
> 2) Re farmlands and forests: I sometimes draw these in, but not often.<br>
> I agree with you that it seems helpful to give a rough picture of the<br>
> landscape to expect, BUT on the other hand, I think having these<br>
> polygons all over can sometimes make the more important jobs harder:<br>
> jobs such as checking that every single building has been captured.<br>
> And since these landuse polygons are pretty much never requested in<br>
> the tasks (apart from landuse=residential which is often a crucial<br>
> first step), it seems the locals and the aid organisations don't<br>
> particularly need them. So I would suggest don't spend much time on<br>
> those.<br>
<br>
</div>Ah, allright. Well, I prioritize anyway; if I'm in the mood I'll just<br>
draw it anyway :-)<br></blockquote><div>I would say it depends on the situation. Eg in Khartoum (<a href="http://www.openstreetmap.org/#map=12/15.7493/32.5389">http://www.openstreetmap.org/#map=12/15.7493/32.5389</a>) 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.<br>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class=""><br>
> If you see tasks which seem fairly complete, it<br>
> might be a better use of your time to get yourself to a point where<br>
> you feel confident enough to *validate* other people's completed<br>
> squares. It takes a little while to feel confident about being a<br>
> validator but we always need more validation effort than we get.<br>
<br>
</div>Good point; however, when it comes to the validating part, I know how<br>
hard that is in my area - especially when it comes to correct road<br>
relations and the such. There are still many grey areas, as soon as we<br>
run out of unaddressed areas, I'll look other the validation part. So<br>
that more skilled people can concentrate on that first. Also, Is there<br>
a feedback process in case I'm doing something wrong? I guess if I<br>
make a mistake, I'll do the same over and over again. Got the wiki in<br>
another tab open for reference at all times, but well, you know how it<br>
is.<br>
<div class=""><br>
> 3) Firstly, you should indeed tag the changeset with the actual<br>
> imagery you used.<br>
<br>
</div>I thought so.<br>
<div class=""><br>
> But secondly, if you're not careful about which<br>
> imagery you use, there's a risk that you might end up tracing from<br>
> imagery that is a couple of years old or something like that.<br>
<br>
</div>Luckily Bing shows a date in JOSM and all of it shows 2014 up until now.<br>
<div class=""><br>
> My personal approach would be to try and use the recommended imagery,<br>
> since someone has usually put effort in to working out which imagery<br>
> is most appropriate. Also, there's usually a conversation on the<br>
> mailing list which always gives some clues about what to use.<br>
<br>
</div>I paid attention to this, however other people seem to have the same<br>
problem - MapBox/Digital Globe is not exactly high-res. In one<br>
occasion I could use Spot data, but that seems to be rare.<br>
<br>
I wonder if it'd be useful to use Sentinel 1-A data? It's free to use<br>
and available at ESA's Sentinel Data Hub. However, the 1-A satellite<br>
was just recently comissioned and the webinterface is a nightmare.<br>
Also, the data products aren't really curated yet, only level-1<br>
products are really useful now and we're speaking about TIFF-blobs<br>
hundreds of Megabytes large. I think these would've to be split to<br>
tiles and zoom-levels first before they're really useful to JOSM.<br>
<br>
Information about ESA's Sentinel project:<br>
<a href="https://sentinel.esa.int/web/sentinel/home" target="_blank">https://sentinel.esa.int/web/sentinel/home</a><br>
Sentinel Data hub: <a href="https://senthub.esa.int/" target="_blank">https://senthub.esa.int/</a><br>
<br>
Regristration and usage is free.<br>
<br>
> Dan<br>
<br>
Alex.<br>
<div class=""><div class="h5"><br>
<br>
--<br>
The best thing about procrastinating is you can do it NOW and ANYTIME.<br>
<br>
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</div></div></blockquote></div><br></div></div>