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#1 2008-03-25 00:18:05

netman55
Member
Registered: 2008-03-21
Posts: 6

Potlatch 0.8 and relations

So potlatch has gone to 0.8, is there any documentation to use relations with potlatch?

I am having trouble getting my head round the use of relations as described in the wiki, anyone know of any good locations on "the Map" so I can look at them in potlatch edit mode, to get a better understanding?

TIA

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#2 2008-03-25 11:29:13

emj
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From: .se (59.3N17.99E) 0735969076
Registered: 2006-06-18
Posts: 949

Re: Potlatch 0.8 and relations

Yeah relations are pretty scary imho I asked something similar awhile back see here:

JRA wrote:

Some people are learning to use multipolygons for drawing building blocks:
http://openstreetmap.org/edit.html?lat= … 58&zoom=17

I changed the url to a good location.

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#3 2008-03-25 12:29:39

netman55
Member
Registered: 2008-03-21
Posts: 6

Re: Potlatch 0.8 and relations

smile Thanks emj, that covers one area of the use of relations with regards to muliipolygons and how its put together in potlatch. I think I could now, for example, represent a building with inner open courtyard.

One area I can't seem to figure out at the moment is the use of relation with respect to route type situations. Let me expand a little. In my area is
the Saxon Shore Way ( a long distance walk around Kent etc). How can this be represented as it follows many different types of highways and
shares its path with other routes, for example, with cycle routes. I think, relations is the way forward here, but not sure how to construct this using potlatch.

Another similar thing, a local tourist office has a leaflet showing a historic walking tour (which they have given a name but is not physically sign posted or only in part) around a city which uses all sorts of highways, goes through buildings (in one entrance out another entrance), crosses roads etc.

Any ideas welcome, examples on "the map" would be even better

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#4 2008-03-25 12:36:22

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Potlatch 0.8 and relations

No instructions about Potlatch unfortunately, but relations can be used to define a local walking route (not sure if this is the correct way and it won't be rendered yet, afaik):

type=route
route=foot
network=lcn
name=[the name of the walk]
note=[some description of the walk/route]


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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#5 2008-03-25 14:58:44

emj
Member
From: .se (59.3N17.99E) 0735969076
Registered: 2006-06-18
Posts: 949

Re: Potlatch 0.8 and relations

Potlatch and relations are pretty easy to workout, it looks pretty nice and clear. What netman55 highlights is the  need of example areas where we can observe how to use relations.

Actually a sand box area would be great.

Last edited by emj (2008-03-25 14:59:45)

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#6 2008-03-25 22:36:44

netman55
Member
Registered: 2008-03-21
Posts: 6

Re: Potlatch 0.8 and relations

Thanks for the info Lambertus.

As mentioned earlier, I could not work out how relations fiited together to make use of them when I looked at the wiki page. I looked at the  examples at the bottom of the page but this only give xml output not how to use relations. When Lambertus mentioned the page I took another look to see if I had missed anything. That give me the idea to look up the national cycle network (NCN) 4 on the cycle map (gravitystorm.co.uk).
Picked on a town (Egham) that the route went through, went to the osm map found Egham and into edit mode of potlatch.
From what emj had suggested as a location example and this Egham location, I found my first learning point.

If a way or node has a relation, in edit mode you can see a "shadow" effect on that way or node.

Selecting a way, and then clicking on the relation a "pop up" gives the detail similar the Lambertus list. I noticed that the relation had a number, it was then I realised this tied up with the xml output on the wiki page.

For ncn 4 the relation id is 2204 so browsing to http://www.openstreetmap.org/api/0.5/relation/2204 gives the ways (members) of the relation.

http://www.openstreetmap.org/api/0.5/relation/2204/full gives even more detail. From this output you can find the long/lat of the ways involved and feed this into search on the map page (now that namefinder works) to see it.

Dutch railway is http://www.openstreetmap.org/api/0.5/relation/4831 which you can see at
http://www.openstreetmap.org/?lat=52.16 … ayers=B0FT

So now to have a go myself, I picked a few ways near my location

Here I am trying to indicate a walking route called Chattenden Woods Walk, this far from complete as the required ways are not all mapped yet.

Into edit mode of potlatch select a footpath way, click on the relation icon to add, in the pop up box I added the following

type=route
route=foot
name=Chattenden Woods Walk

Click ok

This puts a item in the way tag list as foot Chattenden Woods Walk.

Next selected the adjacent way to the above which is a highway way, click on relation icon again, this time you have the relation in thedrop down list so you don't have to enter all the detail of the relation again.

I have now a relation with the id 8470, which can be listed in http://www.openstreetmap.org/api/0.5/relation/8470 and here

http://www.openstreetmap.org/?lat=51.43 … ayers=0BFT

I have also added in a bridleway into the relation but this is some way distant from the above ways (other end of walk)

I did not use network=lcn as this is used for local cycle routes as far as I can see.

Couple of questions:

When adding ways/nodes to a relation in this situation, do they have to be added in sequence?

Thinking about network=*, if I put together a number of walking routes, as these are in the Medway area, would it be appropiate to relate them together with something like network=Local Medway Walks?

Thanks for the help so far guys.

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#7 2008-03-26 09:55:39

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Potlatch 0.8 and relations

Well done, you've found a good way to answer your questions. I'll keep that in mind when the question pops-up again.


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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