Re: [OSM-talk] Broken coastline

[Colin Smale]

 

...And this may be different to the limit of government jurisdiction. In
the UK, local authorities' jurisdiction goes (normally) to MLWS (mean
low water - spring tides), which is beyond the MHWS coastline. Why am I
saying this? Please don't use the same way in both the coastline and the
admin boundary, unless you are absolutely sure they coincide by
definition (not by coincidence). 

//colin 

On 2015-05-11 19:39, Malcolm Herring wrote: 

> On 11/05/2015 18:01, pmailkeey . wrote:
> 
>> Where should the coastline be ? HWM, LWM or MW. What about islands that only 
>> appear at low tide !
> 
> The most common definition is mean high water - spring tides (MHWS)
> 
> ___
> talk mailing list
> talk@openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk [1]
 

Links:
--
[1] https://lists.openstreetmap.org/listinfo/talk
___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Malcolm Herring]

On 11/05/2015 18:01, pmailkeey . wrote:

Where should the coastline be ? HWM, LWM or MW. What about islands that
only appear at low tide !



The most common definition is mean high water - spring tides (MHWS)


___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[pmailkeey .]

Where should the coastline be ? HWM, LWM or MW. What about islands that
only appear at low tide !

On 11 May 2015 at 17:47, Christoph Hormann  wrote:

> On Monday 11 May 2015, Mike Thompson wrote:
> >
> > I don't have a strong preference for how they are represented
> > (natural=coastline or natural=water), but I believe the mix and
> > incomplete implementation of the two approaches is causing rendering
> > issues.
>
> At least the OSM standard style does not have a problem with having both
> coastline and a water multipolygon - the Caspian Sea, Lake Ladoga and
> Lake Onega also all have multipolygon relations tagged natural=water.
>
> The 'half the lake' relation and missing inner rings of course call for
> trouble.
>
> > I have seen a number of them on the Canadian side.  Regardless of the
> > number, finding and editing all of them is going to be tedious and
> > error prone without a way to query for them. I can probably write
> > something that will operate on the file JOSM downloads that will
> > check to make sure I have fixed them all, but would like to leverage
> > existing code as much as possible.
>
> You probably could save the islands after you tagged them as coastline
> from JOSM (only the islands) and run them through osmcoastline as if
> they were the only land on earth and see if there are any
> errors/warnings.
>
> --
> Christoph Hormann
> http://www.imagico.de/
>
> ___
> talk mailing list
> talk@openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk
>



-- 
Mike.
@millomweb  -
For all your info on Millom and South Copeland
via *the area's premier website - *

*currently unavailable due to ongoing harassment of me, my family, property
& pets*

T&Cs 
___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Christoph Hormann]

On Monday 11 May 2015, Mike Thompson wrote:
>
> I don't have a strong preference for how they are represented
> (natural=coastline or natural=water), but I believe the mix and
> incomplete implementation of the two approaches is causing rendering
> issues.

At least the OSM standard style does not have a problem with having both 
coastline and a water multipolygon - the Caspian Sea, Lake Ladoga and 
Lake Onega also all have multipolygon relations tagged natural=water.

The 'half the lake' relation and missing inner rings of course call for 
trouble.

> I have seen a number of them on the Canadian side.  Regardless of the
> number, finding and editing all of them is going to be tedious and
> error prone without a way to query for them. I can probably write
> something that will operate on the file JOSM downloads that will
> check to make sure I have fixed them all, but would like to leverage
> existing code as much as possible.

You probably could save the islands after you tagged them as coastline 
from JOSM (only the islands) and run them through osmcoastline as if 
they were the only land on earth and see if there are any 
errors/warnings.

-- 
Christoph Hormann
http://www.imagico.de/

___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Mike Thompson]

On Mon, May 11, 2015 at 1:36 AM, Christoph Hormann 
 wrote:

> On Sunday 10 May 2015, Mike Thompson wrote:
> > I am considering an edit involving "natural=coastline" involving the
> > Great Lakes that are shared between the US and Canada.  This has been
> > discussed on the Talk-US and Talk-Ca lists and there have been no
> > objections to date.
>
> As you know the Great Lakes have a right of continuance in being tagged
> as coastline however you should keep in mind that not having a
> multipolygon relation tagged natural=water representing these lakes
> also has disadvantages, and having relations/nodes tagged place=sea or
> place=lake is awkward and you can't really expect geocoders, renderers
> and other programs to make a special case here.
>
I don't have a strong preference for how they are represented
(natural=coastline or natural=water), but I believe the mix and incomplete
implementation of the two approaches is causing rendering issues.



> > Technical advice is welcome, e.g. how to easily find island ways that
> > go clockwise (water on the left)
>
> Yes, that's a tricky one - i don't think there are that many islands not
> yet tagged coastline though.

I have seen a number of them on the Canadian side.  Regardless of the
number, finding and editing all of them is going to be tedious and error
prone without a way to query for them. I can probably write something that
will operate on the file JOSM downloads that will check to make sure I have
fixed them all, but would like to leverage existing code as much as
possible.

>
>

>
> By the way even if the lakes are tagged as coastline tagging the
> US-Canada boundary within the lakes maritime=yes is not correct.
>
Good to know.  There actually appears to be two sets of ways in that area,
one set is part of the Canadian Lake Superior relation, and the other part
of the Canadian and US boundary relations.

Mike Thompson
___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Christoph Hormann]

On Sunday 10 May 2015, Mike Thompson wrote:
> I am considering an edit involving "natural=coastline" involving the
> Great Lakes that are shared between the US and Canada.  This has been
> discussed on the Talk-US and Talk-Ca lists and there have been no
> objections to date.

As you know the Great Lakes have a right of continuance in being tagged 
as coastline however you should keep in mind that not having a 
multipolygon relation tagged natural=water representing these lakes 
also has disadvantages, and having relations/nodes tagged place=sea or 
place=lake is awkward and you can't really expect geocoders, renderers 
and other programs to make a special case here.

By the way even if the lakes are tagged as coastline tagging the 
US-Canada boundary within the lakes maritime=yes is not correct.

> Technical advice is welcome, e.g. how to easily find island ways that
> go clockwise (water on the left)

Yes, that's a tricky one - i don't think there are that many islands not 
yet tagged coastline though.

-- 
Christoph Hormann
http://www.imagico.de/

___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Mike Thompson]

I am considering an edit involving "natural=coastline" involving the Great
Lakes that are shared between the US and Canada.  This has been discussed
on the Talk-US and Talk-Ca lists and there have been no objections to date.

Background:
Lake Superior is represented both with individual ways tagged
"natural=coastline" (although not all islands have their ways tagged
"natural=coastline"), as well as *two* multipolygon relations tagged
"natural=water" (this tag has been removed from the one relation already)
with some islands members having a role of "inner." The first (for the
purpose of the discussion) relation seems to include the entire outline of
the lake, but not all of the islands, particularly on the Canadian side.
The second includes only the outline of the lake on the Canadian side, and
the part of the border between the US and Canada that runs through the
lake.  It appears that this second relation does include all, or nearly
all, of the islands on the Canadian side. Representing the lake and its
islands in these multiple manners seems to cause rendering issues.

Proposed Course of action.
1) Download Canadian Lake Superior relation and all its members to JOSM.
2) Make sure every individual member way is tagged "natural=coastline"
(except the way(s) that form the boundary between Canada and the US.
3) Make sure every individual way has land on the left. (except the US
Canadian border that runs through the lake).
4) Remove "natural=water" from the Canadian relation
5) Upload.

Later
6) Make sure all members of the Canadian relation appear in the overall
relation (or that their purpose is filled my some other member(s) of the
overall relation.
7) Delete the Canadian relation.

Comments are welcome.

Technical advice is welcome, e.g. how to easily find island ways that go
clockwise (water on the left)

Mike (user: tekim)


On Sun, May 10, 2015 at 9:51 AM, Christoph Hormann 
wrote:

> On Sunday 10 May 2015, Jochen Topf wrote:
> > Hi!
> >
> > For about 10 days the coastline has been broken and no updates have
> > been going through. This is largely due to some broken mapping in
> > North America where coastlines overlap and some features have been
> > tagged both as coastline and waterways, which doesn't make any sense
> > at all.
>
> Note overlaps between waterway=riverbank areas and the coastline are
> generally not an issue and are also not really that uncommon (classic
> and long term case for that it the Elbe in northern Germany) - they of
> course complicate things a bit and can be misleading for mappers.
>
> > Please, everybody: If you are doing something with the coastlines,
> > take extra care. Coastlines are fragile, have special taggging rules
> > unlike anything else in OSM and if you break them in only one place,
> > chances are coastlines updates for the whole world will stop!
>
> Indeed.  And if you have a complex coastline situation like when you
> need to add or remove the coastline tag to/from a larger water area and
> have not done something like this before just leave the coastline
> mapping as it is and add a fixme tag indicating what should be changed
> and place a note asking for help doing that.
>
> --
> Christoph Hormann
> http://www.imagico.de/
>
> ___
> talk mailing list
> talk@openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk
>
___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Christoph Hormann]

On Sunday 10 May 2015, Jochen Topf wrote:
>
> For about 10 days the coastline has been broken and no updates have
> been going through. This is largely due to some broken mapping in
> North America where coastlines overlap 

I fixed the error in the Laguna Madre - making it a multipolygon.  There 
is however still a lot of strange stuff with the mapping of the various 
lagoons and inlets along the gulf coast - the US community should have 
a more thorough look there and make some decisions about sensible 
divisions between the different waterbodies.  And when you implement 
that be careful with the coastline please.

-- 
Christoph Hormann
http://www.imagico.de/

___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken coastline

[Christoph Hormann]

On Sunday 10 May 2015, Jochen Topf wrote:
> Hi!
>
> For about 10 days the coastline has been broken and no updates have
> been going through. This is largely due to some broken mapping in
> North America where coastlines overlap and some features have been
> tagged both as coastline and waterways, which doesn't make any sense
> at all.

Note overlaps between waterway=riverbank areas and the coastline are 
generally not an issue and are also not really that uncommon (classic 
and long term case for that it the Elbe in northern Germany) - they of 
course complicate things a bit and can be misleading for mappers.

> Please, everybody: If you are doing something with the coastlines,
> take extra care. Coastlines are fragile, have special taggging rules
> unlike anything else in OSM and if you break them in only one place,
> chances are coastlines updates for the whole world will stop!

Indeed.  And if you have a complex coastline situation like when you 
need to add or remove the coastline tag to/from a larger water area and 
have not done something like this before just leave the coastline 
mapping as it is and add a fixme tag indicating what should be changed 
and place a note asking for help doing that.

-- 
Christoph Hormann
http://www.imagico.de/

___
talk mailing list
talk@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken Coastline?

[Tristan Scott]

I changed the direction of cockshoot broad (it was indeed spun
backwards) but couldn't fin anything wrong with the coastline -
possibly someone had already fixed it, possibly a bad tile
temporarily?
anyway, seems ok now.

Thanks, all!

Tristan

2008/10/22 Rob Reid <[EMAIL PROTECTED]>:
> Tristan Scott wrote the following on 20/10/2008 04:27:
>> I've modded the coastline here:
>> http://www.openstreetmap.org/?lat=52.7145&lon=1.695&zoom=14&layers=0B00FTTT
>>
>> And yet all I've done is move about 4 points in a bit, and add a
>> section of beach where I went for a walk. And now some of the new
>> tiles in osmarender seem to have gone blue... I can't see what I've
>> got wrong.
>> Can someone have a squint and see if there's something wrong? (I've
>> never edited a coastline before, so don't know how they work)
>>
>>
> Not sure if anyone else has made changes since your email but I just had
> a look and everything looked fine so I re-rendered the  problem tile and
> everything looks good again.
> The re-render covers zoom 12 -17, it may be a few days before lower
> zooms are updated.
>
> rcr
>
>
> ___
> talk mailing list
> talk@openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk
>



-- 
Tristan Scott BSc(Hons)
Yare Valley Technical Services
www.yvts.co.uk
07837 205829

___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken Coastline?

[Rob Reid]

Tristan Scott wrote the following on 20/10/2008 04:27:
> I've modded the coastline here:
> http://www.openstreetmap.org/?lat=52.7145&lon=1.695&zoom=14&layers=0B00FTTT
>
> And yet all I've done is move about 4 points in a bit, and add a
> section of beach where I went for a walk. And now some of the new
> tiles in osmarender seem to have gone blue... I can't see what I've
> got wrong.
> Can someone have a squint and see if there's something wrong? (I've
> never edited a coastline before, so don't know how they work)
>
>   
Not sure if anyone else has made changes since your email but I just had 
a look and everything looked fine so I re-rendered the  problem tile and 
everything looks good again.
The re-render covers zoom 12 -17, it may be a few days before lower 
zooms are updated.

rcr


___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk

Re: [OSM-talk] Broken Coastline?

[Roman Neumüller]

Opening your link with zoom=9 instead of 14 shows lots of errors and
warnings; JOSM's validator shows for example

   Reversed water: land not on left side (2)
 (101 nodes)
 Cockshoot Broad (12 nodes)

Maybe it's that...

Roman

> Date: Sun, 19 Oct 2008 16:27:35 +0100
> From: "Tristan Scott" <[EMAIL PROTECTED]>
> Subject: [OSM-talk] Broken Coastline?
> To: talk@openstreetmap.org
> Message-ID:
>   <[EMAIL PROTECTED]>
> Content-Type: text/plain; charset=ISO-8859-1
> I've modded the coastline here:
> http://www.openstreetmap.org/?lat=52.7145&lon=1.695&zoom=14&layers=0B00FTTT
> And yet all I've done is move about 4 points in a bit, and add a
> section of beach where I went for a walk. And now some of the new
> tiles in osmarender seem to have gone blue... I can't see what I've
> got wrong.
> Can someone have a squint and see if there's something wrong? (I've
> never edited a coastline before, so don't know how they work)
> Thanks
>



___
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk