Re: [OSM-talk] Mulltipolygons and Mapnik

[Martijn van Oosterhout]

On Sat, May 31, 2008 at 9:32 PM, Jon Burgess <[EMAIL PROTECTED]> wrote:
> I believe the sites are both using very similar code (unless Kleptog has
> some private changes for the NL site). I think the difference may be due
> to the NL site using the "--slim" mode. In this case this is probably
> allowing it to keep the untagged inner way that would have been
> discarded in non-slim mode.

Correct, the --slim mode makes all the difference.

The basic problem is that to manage such relations it needs to
remember the relevent ways for when it processes the relations. When
processing a whole planet dump it obviously can't rememeber all the
ways in memory, which is why non-slim mode doesn't get it. Slim mode
remembers everything and so it always works.

It would be possible to get non-slim mode to work also by processing
relations first. As usual, needs a coder.

Have a nice day,
-- 
Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Jon Burgess]

On Sat, 2008-05-31 at 22:05 +0200, Cartinus wrote:
> On Saturday 31 May 2008 21:26:53 Jon Burgess wrote:
> > On Sat, 2008-05-31 at 20:08 +0200, Cartinus wrote:
> > > I forgot to mention:
> > >
> > > A hole filled with something else IOW different tags on the outer and
> > > inner polygons only works in [EMAIL PROTECTED]/Osmarender
> > >
> > > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=000
> > >000BF
> > > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=000
> > >00B0F
> > > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=B00
> > >F
> >
> > I'm not certain which polygons you are talking about here. If you are
> > talking about the ones to the NW, then those look like they are marked
> > with area=yes. Support for area=yes was only recently added to the
> > osm2pgsql code and the rendering styles have not been implemented yet.
> >
> > Mapnik will render inner areas with different tags. It uses the area of
> > the polygons to figure out the render ordering. Smaller areas always
> > render on top of larger areas of the same layer. If the layer tags
> > differ then this will take precedence.
> >
> > Jon
> 
> The area=yes stuff has nothing to do with multipolygons. There is only one 
> multipolygon in the view I linked to. (relationID=9214; name=Meubelboulevard)
> 
> Click on the first link. Right in the middle you'll see a park surrounded by 
> a 
> retail area.
> 
> Now switch to either of the two Mapnik renders. At the western end of where 
> the park showed in the Osmarender view (just below the parking icon) you can 
> see some edgeline between retail and retail (except the inner retail should 
> be park). Around the rest of the park this is obscured by roads.

OK I see it now. The multipolygon is for the outer retail area and the
inner 'hole' way is tagged for the park. As you say, this does not work
with Mapnik. It is still basing its assumptions on the inner holes being
tagged the same as the outer ring. If you need to put a park into the
hole then this needs to a another way (even it it uses the same nodes).

Avoiding this duplication of ways was the aim of the suggestion as
documented on the wiki that tags on the inner ways should always be
ignored. As you say, this does not work with Mapnik at present.

Jon



___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Cartinus]

On Saturday 31 May 2008 21:26:53 Jon Burgess wrote:
> On Sat, 2008-05-31 at 20:08 +0200, Cartinus wrote:
> > I forgot to mention:
> >
> > A hole filled with something else IOW different tags on the outer and
> > inner polygons only works in [EMAIL PROTECTED]/Osmarender
> >
> > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=000
> >000BF
> > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=000
> >00B0F
> > http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=B00
> >F
>
> I'm not certain which polygons you are talking about here. If you are
> talking about the ones to the NW, then those look like they are marked
> with area=yes. Support for area=yes was only recently added to the
> osm2pgsql code and the rendering styles have not been implemented yet.
>
> Mapnik will render inner areas with different tags. It uses the area of
> the polygons to figure out the render ordering. Smaller areas always
> render on top of larger areas of the same layer. If the layer tags
> differ then this will take precedence.
>
>   Jon

The area=yes stuff has nothing to do with multipolygons. There is only one 
multipolygon in the view I linked to. (relationID=9214; name=Meubelboulevard)

Click on the first link. Right in the middle you'll see a park surrounded by a 
retail area.

Now switch to either of the two Mapnik renders. At the western end of where 
the park showed in the Osmarender view (just below the parking icon) you can 
see some edgeline between retail and retail (except the inner retail should 
be park). Around the rest of the park this is obscured by roads.

-- 
m.v.g.,
Cartinus

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Robert Vollmert]

On May 31, 2008, at 19:27, Chris Hill wrote:

> I've already changed the wiki to match this situation.  This is the  
> way
> it was, so we are just back to the same position before it was changed
> (in my view) erroneously.

> I also thing this makes logical sense too.  The outer marks the edge  
> of
> the water and so does the inner.  There is a short discuusion on the
> wiki talk page.

As far as I can tell, the main argument for this reversion is "that's  
what the renderers want".

I wonder why those who claim the change was wrong didn't speak up in  
the lengthy discussions in March? (Starting at 
http://lists.openstreetmap.org/pipermail/talk/2008-March/023876.html 
  and http://lists.openstreetmap.org/pipermail/dev/2008-March/009345.html 
, and I do remember one opposing opinion which I can't find.)

Cheers
Robert



___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Jon Burgess]

On Sat, 2008-05-31 at 19:54 +0200, Cartinus wrote:
> Here in Utrecht I have drawn a building with a "courtyard". The inner
> polygon 
> does not have any tags.
> * The hole shows OK in [EMAIL PROTECTED]/Osmarender
> http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=00BF
> * The hole does not show in the osm2pgsql/Mapnik generated tiles from 
> openstreetmap.org.
> http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=0B0F
> * The hole shows OK in the osm2pgsql/Mapnik generated tiles from 
> openstreetmap.nl.
> http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=B00F
> 
> I think openstreetmap.nl uses a newer version of osm2pgsql than the
> main site. 
> If that is true than it is just a question of time till multipolygons
> defined 
> as per wiki description will show OK on the main site too.

I believe the sites are both using very similar code (unless Kleptog has
some private changes for the NL site). I think the difference may be due
to the NL site using the "--slim" mode. In this case this is probably
allowing it to keep the untagged inner way that would have been
discarded in non-slim mode. 

> A multipolygon with the same tags on inner and outer shows OK at all
> three:
> http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=00BF
> http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=0B0F
> http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=B00F
> 
Right, this is normally the best approach.

Jon



___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Jon Burgess]

On Sat, 2008-05-31 at 20:08 +0200, Cartinus wrote:
> I forgot to mention:
> 
> A hole filled with something else IOW different tags on the outer and inner 
> polygons only works in [EMAIL PROTECTED]/Osmarender
> 
> http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=00BF
> http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=0B0F
> http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=B00F

I'm not certain which polygons you are talking about here. If you are
talking about the ones to the NW, then those look like they are marked
with area=yes. Support for area=yes was only recently added to the
osm2pgsql code and the rendering styles have not been implemented yet.

Mapnik will render inner areas with different tags. It uses the area of
the polygons to figure out the render ordering. Smaller areas always
render on top of larger areas of the same layer. If the layer tags
differ then this will take precedence.

Jon




___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Chris Hill]

Dermot McNally wrote:
> 2008/5/31 Chris Hill <[EMAIL PROTECTED]>:
>
>   
>> I've already changed the wiki to match this situation.  This is the way it
>> was, so we are just back to the same position before it was changed (in my
>> view) erroneously.
>> 
>
> Hmm. Could you have missed a bit?
>
> "Tags on inner ways describe the hole. If it's just a hole, leave it 
> untagged."
>
> Dermot
>
>   
Er, yeah, so I had another go with my eyes open this time.

Chris

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/31 Chris Hill <[EMAIL PROTECTED]>:

> I've already changed the wiki to match this situation.  This is the way it
> was, so we are just back to the same position before it was changed (in my
> view) erroneously.

Hmm. Could you have missed a bit?

"Tags on inner ways describe the hole. If it's just a hole, leave it untagged."

Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Cartinus]

I forgot to mention:

A hole filled with something else IOW different tags on the outer and inner 
polygons only works in [EMAIL PROTECTED]/Osmarender

http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=00BF
http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=0B0F
http://tile.openstreetmap.nl/?zoom=17&lat=52.06243&lon=5.10283&layers=B00F

(You can just use the layer switcher on the page in stead of opening each link 
separately.)

-- 
m.v.g.,
Cartinus

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Cartinus]

On Saturday 31 May 2008 19:07:31 Dermot McNally wrote:
> Multipolygons with untagged inner elements (per wiki): Don't render on
> Mapnik Multipolygons with inner elements tagged as the outer ones: Do
> render on Mapnik
>
> At this point, we _could_ define the current behaviour as a standard,
> update the wiki and change whatever data isn't compliant.
>
> *or* we can see if the Mapnik brains are willing/able to support
> multipolygons according to the current wiki instructions.

Here in Utrecht I have drawn a building with a "courtyard". The inner polygon 
does not have any tags.
* The hole shows OK in [EMAIL PROTECTED]/Osmarender
http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=00BF
* The hole does not show in the osm2pgsql/Mapnik generated tiles from 
openstreetmap.org.
http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=0B0F
* The hole shows OK in the osm2pgsql/Mapnik generated tiles from 
openstreetmap.nl.
http://tile.openstreetmap.nl/?zoom=17&lat=52.08396&lon=5.10485&layers=B00F

I think openstreetmap.nl uses a newer version of osm2pgsql than the main site. 
If that is true than it is just a question of time till multipolygons defined 
as per wiki description will show OK on the main site too.

A multipolygon with the same tags on inner and outer shows OK at all three:
http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=00BF
http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=0B0F
http://tile.openstreetmap.nl/?zoom=15&lat=52.05845&lon=5.16772&layers=B00F


-- 
m.v.g.,
Cartinus

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Chris Hill]

Dermot McNally wrote:
> 2008/5/23 Chris Hill <[EMAIL PROTECTED]>:
>
>   
>> I took the liberty of changing the islands to match their outer so I expect
>> it to render.
>> 
>
> One Mapnik render later, we have some solid data:
>
> Multipolygons with untagged inner elements (per wiki): Don't render on Mapnik
> Multipolygons with inner elements tagged as the outer ones: Do render on 
> Mapnik
>
> At this point, we _could_ define the current behaviour as a standard,
> update the wiki and change whatever data isn't compliant.
>
> *or* we can see if the Mapnik brains are willing/able to support
> multipolygons according to the current wiki instructions.
>
> I don't really mind which, since certainty is all we really need here.
>
> Opinions?
> Dermot
I've already changed the wiki to match this situation.  This is the way 
it was, so we are just back to the same position before it was changed 
(in my view) erroneously.

I also thing this makes logical sense too.  The outer marks the edge of 
the water and so does the inner.  There is a short discuusion on the 
wiki talk page.

Cheers, Chris

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/23 Chris Hill <[EMAIL PROTECTED]>:

> I took the liberty of changing the islands to match their outer so I expect
> it to render.

One Mapnik render later, we have some solid data:

Multipolygons with untagged inner elements (per wiki): Don't render on Mapnik
Multipolygons with inner elements tagged as the outer ones: Do render on Mapnik

At this point, we _could_ define the current behaviour as a standard,
update the wiki and change whatever data isn't compliant.

*or* we can see if the Mapnik brains are willing/able to support
multipolygons according to the current wiki instructions.

I don't really mind which, since certainty is all we really need here.

Opinions?
Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Chris Hill]

Dermot McNally wrote:
> 2008/5/23 Chris Hill <[EMAIL PROTECTED]>:
>   
>> I've worked with islands before.  It seems that the key points are:
>> 1. make sure that the same tag is used on the inner and outer, in this case
>> natural=water
>> 2. Make sure that the outer is clockwise and inner(s) are anticlockwise
>>
>> I took the liberty of changing the islands to match their outer so I expect
>> it to render.
>> 
>
> It's worth a try, and we'll know in a week, but I'm not so sure this
> will cure the problem. Otherwise, how do you explain the island that
> already was tagged the same but still didn't render on the mapnik
> layer? I'm also about 90% sure that I've seen untagged islands with an
> inner role in the relations showing up OK in the past.
>
> Regardless, we need to decide:
>
> * What version of this tagging we think _should_ be considered correct.
> * Ensure both main renderers will accept the "valid" form.
> * Adapt the wiki as required to reflect reality
>
> Dermot
>
>   
it is possible that multiple holes (islands in this case) don't render 
properly.  All of the islands I've drawn have only had a single island 
in each body of water.  Let's see what happens ...

Cheers, Chris

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Martijn van Oosterhout]

On Sat, May 24, 2008 at 1:01 AM, Dermot McNally <[EMAIL PROTECTED]> wrote:
> It's worth a try, and we'll know in a week, but I'm not so sure this
> will cure the problem. Otherwise, how do you explain the island that
> already was tagged the same but still didn't render on the mapnik
> layer? I'm also about 90% sure that I've seen untagged islands with an
> inner role in the relations showing up OK in the past.

Also, when reporting these kinds of issues it's very helpful to
provide the ID of the relation, because then it only takes seconds to
see if its tagged properly. Don't discount the possibility of bugs in
renderers

Have a nice day,
-- 
Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/23 Chris Hill <[EMAIL PROTECTED]>:
> I've worked with islands before.  It seems that the key points are:
> 1. make sure that the same tag is used on the inner and outer, in this case
> natural=water
> 2. Make sure that the outer is clockwise and inner(s) are anticlockwise
>
> I took the liberty of changing the islands to match their outer so I expect
> it to render.

It's worth a try, and we'll know in a week, but I'm not so sure this
will cure the problem. Otherwise, how do you explain the island that
already was tagged the same but still didn't render on the mapnik
layer? I'm also about 90% sure that I've seen untagged islands with an
inner role in the relations showing up OK in the past.

Regardless, we need to decide:

* What version of this tagging we think _should_ be considered correct.
* Ensure both main renderers will accept the "valid" form.
* Adapt the wiki as required to reflect reality

Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Chris Hill]

I've worked with islands before.  It seems that the key points are:
1. make sure that the same tag is used on the inner and outer, in this 
case natural=water
2. Make sure that the outer is clockwise and inner(s) are anticlockwise

I took the liberty of changing the islands to match their outer so I 
expect it to render.

Cheers, chris

Dermot McNally wrote:
> 2008/5/23 Ludwig <[EMAIL PROTECTED]>:
>   
>> The holes, at least for my example, are land (so natural=land).
>> 
>
> It's not what's causing the problem, but to me that's just incorrect.
> Valid tagging to me could be:
>
> Untagged: It's just a hole in whatever its parent polygon is.
> Tagged water: It's a hole in something that is water, so it identifies
> itself as a "water hole"
>
> To tag it as land _and_ make it part of a multipolygon seems to be a
> double negative.
>
> Dermot
>
>   

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Cartinus]

On Friday 23 May 2008 21:18:40 Ludwig wrote:
>- Land that exists within another area, such as a lake. (i.e an island).
>Keep water on the right and land on the left side in relation to
> sequence of nodes in the Way. Layering may also be required. See
>  
>  Relations/Multipolygonultipolygon>for islands in lakes

You either hack around with natural=land and layers (which is bad practice 
IMHO) or you use multipolygons. Trying to do both at once is just weird (and 
not really what that text is trying to say.)

- - - - - - - - 

After the last round of discussions about how to tag multipolygons I left some 
tagged in different ways around my home city. I just checked the current 
state of their renders.

1)
outer tagged with feature X & inner tagged with feature X
- Works with osm2pgsql used on the main site (i.e. the mapnik layer)
- Works with Osmarender

2)
outer tagged with feature X & inner not tagged at all
- Does not work with osm2pgsql used on the main site (i.e. the mapnik layer)
- Works with Osmarender

3)
outer tagged with feature X & inner tagged with feature Y
- Does not work with osm2pgsql used on the main site (i.e. the mapnik layer)
- Does not work with Osmarender

So your first example doesn't show the islands because they are not having 
tags. I don't know why the island in the second example doesn't work. The 
relation and both the inner and outer polygon look OK.

-- 
m.v.g.,
Cartinus

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Ludwig]

I was just trying to follow the rules from
http://wiki.openstreetmap.org/index.php/Map_Features:

   - Land that exists within another area, such as a lake. (i.e an island).
   Keep water on the right and land on the left side in relation to sequence of
   nodes in the Way. Layering may also be required. See
   
Relations/Multipolygonfor
islands in lakes

I agree that the land-tag itself is redundant, so maybe the instructions
should change.

Ludwig

2008/5/23 Dermot McNally <[EMAIL PROTECTED]>:

> 2008/5/23 Ludwig <[EMAIL PROTECTED]>:
> > The holes, at least for my example, are land (so natural=land).
>
> It's not what's causing the problem, but to me that's just incorrect.
> Valid tagging to me could be:
>
> Untagged: It's just a hole in whatever its parent polygon is.
> Tagged water: It's a hole in something that is water, so it identifies
> itself as a "water hole"
>
> To tag it as land _and_ make it part of a multipolygon seems to be a
> double negative.
>
> Dermot
>
> --
> --
> Iren sind menschlich
>
___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/23 Ludwig <[EMAIL PROTECTED]>:
> The holes, at least for my example, are land (so natural=land).

It's not what's causing the problem, but to me that's just incorrect.
Valid tagging to me could be:

Untagged: It's just a hole in whatever its parent polygon is.
Tagged water: It's a hole in something that is water, so it identifies
itself as a "water hole"

To tag it as land _and_ make it part of a multipolygon seems to be a
double negative.

Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/23 Jukka Rahkonen <[EMAIL PROTECTED]>:

> Have you tried adding the lake tag (natural=water)also for the holes?  I know 
> it
> works with buildings but I do not know if it is necessary.

It won't help here either - my second example already has the holes
tagged. Good thought, though.

Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Ludwig]

The holes, at least for my example, are land (so natural=land).

2008/5/23 Jukka Rahkonen <[EMAIL PROTECTED]>:

> Dermot McNally  gmail.com> writes:
>
> >
>
> > Unfortunately, I don't think that's the problem:
> >
> >
>
> http://geo.topf.org/comparison/index.html?mt0=tah&mt1=mapnik&lon=-8.1250762&lat=53.9649733&z=13
> >
> > This example has only one island, and that doesn't show either.
> >
> > Dermot
>
>
> Hi,
>
> Have you tried adding the lake tag (natural=water)also for the holes?  I
> know it
> works with buildings but I do not know if it is necessary.
>
> -Jukka Rahkonen-
>
>
>
>
>
> ___
> talk mailing list
> talk@openstreetmap.org
> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
>
___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Jukka Rahkonen]

Dermot McNally  gmail.com> writes:

>

> Unfortunately, I don't think that's the problem:
> 
>
http://geo.topf.org/comparison/index.html?mt0=tah&mt1=mapnik&lon=-8.1250762&lat=53.9649733&z=13
> 
> This example has only one island, and that doesn't show either.
> 
> Dermot


Hi,

Have you tried adding the lake tag (natural=water)also for the holes?  I know it
works with buildings but I do not know if it is necessary.

-Jukka Rahkonen-





___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Dermot McNally]

2008/5/23 Ludwig <[EMAIL PROTECTED]>:
> I noticed this also. Without investigating it any further, my hunch was that
> only the first island is rendered.
>
> This lake has two islands, but only one shows up in Mapnik:

Unfortunately, I don't think that's the problem:

http://geo.topf.org/comparison/index.html?mt0=tah&mt1=mapnik&lon=-8.1250762&lat=53.9649733&z=13

This example has only one island, and that doesn't show either.

Dermot

-- 
--
Iren sind menschlich

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk

Re: [OSM-talk] Mulltipolygons and Mapnik

[Ludwig]

I noticed this also. Without investigating it any further, my hunch was that
only the first island is rendered.

This lake has two islands, but only one shows up in Mapnik:

http://geo.topf.org/comparison/index.html?mt0=tah&mt1=mapnik&x=1959&y=1305&z=12

Ludwig

2008/5/23 Dermot McNally <[EMAIL PROTECTED]>:

> Folks,
>
> I've just noticed that the Mapnik layer isn't showing islands
> correctly in some lakes where I had modelled them as "holes" via
> multipolygon relations. Example:
>
>
> http://geo.topf.org/comparison/index.html?mt0=tah&mt1=mapnik&x=1959&y=1305&z=12
>
> I thought that Mapnik was able to handle this. Am I mistaken, or might
> there be recent breakage?
>
> Thanks,
> Dermot
>
> --
> --
> Iren sind menschlich
>
> ___
> talk mailing list
> talk@openstreetmap.org
> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
>
___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk