[OSM-newbies] Startup mapping questions

[Mark Williams]

Piet Stevens wrote:
> Hi,
>
> I have been fascinated by the openstreetmap project, but now I have 
> the following questions:
> a. working with JOSM vs with Potlatch: I have found working with 
> Potlatch easier. I have been unable to get a Yahoo background to JOSM 
> because where to find wms plugin? The chippy5000 etc... path is never 
> available.
>
Me neither - I used it in the pastm, but have largely moved my interest 
outside its coverage so haven't tried too hard.
> b. when uploading traces with Potlatch, I receive immediate feedback 
> on whether the upload succeeded, and I can see all traces I have 
> uploaded, so it is easy to keep track. I cannot find such 
> functionality in JOSM. But then, if I want to work on those traces in 
> JOSM, when I download from OSM into JOSM, I get no traces. Why? Is 
> that normal? When JOSM uploads, does it upload any traces?
>
You should get your new traces from Potlatch immediately, and 
vice-versa. You have selected the 'OpenStreetMap data' checkbox in the 
josm download dialog?

> c. what happens if I edit an area with JOSM and upload, and before I 
> see anything on the map, I also edit this area in Potlatch? Which set 
> of data will be there?
>
Both :( - You should see the new traces in Potlatch though. Tiles take a 
while to regenerate (Mapnik layer on Wednesday, Osmarender after a 
couple of days though you can make it do it faster, see tiles at home).
> e. I started to add tags to ways. It is not clear whether I should 
> copy the tag to every way that makes up 1 street, or whether it is 
> enough to add the tag to 1 way.
>
All ways should have tags. Bearing in mind that a way could be 
o---------o----------o (One tag set) or o-------o< branch, you can't 
have the way do this so it has to be several ways, each will need to be 
tagged. This can look a bit odd when it renders with ever bit named, but 
routing apps will need it one day.
> f. I am uploading traces and ways in Shanghai, China. We have 
> residential streets with 2 lanes in each direction and a middle 
> divider. Should I call that a residential street or not?
>
I don't know Shanghai, you could post a photo somewhere? I would think 
though that if it's a slow, local road it's residential, if it's a 
through route that people happen to live beside, it's not. If the divide 
is wide enough, draw it as dual ways as you would a big trunk road, but 
tag it residential.
> g. I understand that for dual carriageways, the points should be in 
> pairs. I find that difficult to do. I usually put a way in one 
> direction, to ensure all the ways point in the right direction, and 
> then at the end of the trace, I turn back, and put ways in the other 
> direction. Is there an easy process to ensure the points are always in 
> pairs?
>
Just put the second lot alongside the first :)
-----o------o-------
-----o------o-------
> h. in JOSM, I find it difficult to delete a point or a way. Can 
> someone re-clarify the instructions? (select way, shift-click on 
> point, delete does not seem to delete the way)
Select way or node, delete. If your node is in a way, then you have 
(AFAIK) to remove the way, then the node, then rebuild the way. It may 
be easier to split the way, remove a bit, then re-join it. I isn't often 
necessary to do this as extra nodes don't hurt.
>
> i. I have a case where 1 street is currently made up of 2 ways, but I 
> cannot seem to join them as per the instructions. I select one way, 
> and then shift-clicking on the other should join, but nothing happens. 
> Any idea why that could be?
As you say, then pick 'combine ways' from the Tools menu.
>
> g. We also have elevated highways on top of normal streets. I 
> understand I should put these on different layers. But do I then put 2 
> ways on top of each other, with the normal street (layer 0) wider than 
> the elevated highway? How to do that?
Yes, if the lower way is in fact wider you can specify width or lanes 
tags, if it isn't then it's going to be hidden - but you'll see the 
entry/exit going in, and you can use layers + a bridge=yes tag to mark 
the upper one and it will draw edges on it to make it clear.