Re: [OSM-dev] changes in coastline are not rendered

[Martin Koppenhoefer]

2016-02-11 8:11 GMT+01:00 Stephan Knauss :

> This is the reason I suggest against using the simplify functionality.
> Just because some detail level is not to your liking you sort of "tell off"
> those mappers who invested a lot of time putting that details in the first
> place when deleting it.
>
> There are special situations where it can be useful, but in case of
> "hand-drawn" data mostly it is fine to go forward with a handful of
> additional nodes. And don't worry about the size of the data. Those few
> nodes don't do much harm (we have 4 billions already).
>


+1, for the detail I suggest to keep whatever is hand drawn and is a
noticable improvement. To expand on this: If a piece of road is straight,
you shouldn't have more than one node at each end (as long as there aren't
any junctions or other reasons like changing attributes or features on the
road that require additional nodes), but when there are curves you can
obviously add endless nodes to approximate to the shape, and it will always
be smoother. In these cases I'd go with what the mapper has decided to put
and not simplify it automatically (as long as it is an improvement,
sometimes mappers draw many nodes so close but unprecise that the road gets
zigzag curvy because of missing precision, where it actually should be
smooth). In case of overnoding I suggest to improve the geometry manually,
because the douglas peucker algorithm that simplifies only by distance will
introduce problems in sharp curves/turns and leads to a loss of detail.

FWIW, any data consumer that needs simplified geometry can automatically
apply the algorithm and reduce the nodes by himself if that is what he
needs. Reducing is always easier, but enhancing detail automatically is not
possible.

Cheers,
Martin
___
dev mailing list
dev@openstreetmap.org
https://lists.openstreetmap.org/listinfo/dev

Re: [OSM-dev] changes in coastline are not rendered

[Paul Norman]

On 2/11/2016 11:03 AM, Oleksiy Muzalyev wrote:
I assume the old versions are kept in separate tables, and they are 
not used for rendering. 


Old versions are not present on the rendering servers at all.

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

Re: [OSM-dev] changes in coastline are not rendered

[Oleksiy Muzalyev]

On 10/02/16 21:57, Mateusz Konieczny wrote:

On Tue, 9 Feb 2016 11:21:37 +0100
Oleksiy Muzalyev  wrote:


On the other hand, I am in doubt, - perhaps, people invested a lot of
time and labor in clicking these hundreds and hundreds of nodes, to
make a nice looking map, and I am not sure if I am doing the right
thing with the tool SHIFT+Y (Simplify Way). Maybe this excessive
number of nodes is negligible for the database and rendering?

I am not sure is there real benefit from way simplification - except
extreme cases with distance between nodes that is below 1m.

Note that it is not reducing size of the main OSM database - as anyway
all old version are stored forever, so any edit will increase its size.
Certainly, I use Simplify Way only in extreme cases, and only if a 
geometry is not worsened. Even if I use it, I always adjust the geometry 
manually afterwards. Usually these are small lakes, short paths, and 
secondary roads. I never simplify sea or ocean coastlines.


At the last conference in New York I asked a man from UK who works with 
the OSM hardware why at the zoom levels 10, 11, 12 the OSM map is 
rendered only once a month. He replied that the rendering program must 
process enormous amount of data at these zoom levels.


Nowadays a lot of landuse=, natural=, etc. is being added in Ukraine, in 
Russia, Kazakhstan, etc. There are also a lot of landuse and natural in 
the USA which are not mapped yet, the same for Africa. These are very 
large territories, that is why I tried to pay attention to obvious 
over-nodding. The disks capacity and processing power are constantly 
growing, so sooner or later it will not be an issue for sure, the 
question is if they are growing fast enough. However, it seems that this 
my concern could be unfounded.


I assume the old versions are kept in separate tables, and they are not 
used for rendering.


brgds,
Oleksiy

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

Re: [OSM-dev] changes in coastline are not rendered

[Mateusz Konieczny]

On Tue, 9 Feb 2016 11:21:37 +0100
Oleksiy Muzalyev  wrote:

> On the other hand, I am in doubt, - perhaps, people invested a lot of 
> time and labor in clicking these hundreds and hundreds of nodes, to
> make a nice looking map, and I am not sure if I am doing the right
> thing with the tool SHIFT+Y (Simplify Way). Maybe this excessive
> number of nodes is negligible for the database and rendering?

I am not sure is there real benefit from way simplification - except
extreme cases with distance between nodes that is below 1m.

Note that it is not reducing size of the main OSM database - as anyway
all old version are stored forever, so any edit will increase its size.

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

Re: [OSM-dev] changes in coastline are not rendered

[Mateusz Konieczny]

On Mon, 8 Feb 2016 20:20:39 +0100
Christoph Hormann  wrote:

> On Monday 08 February 2016, Gerd Petermann wrote:
> >
> > It was changed more than 3 days ago and the change is not rendered.
> >
> > I understand that coastline ways are special, but that seems too
> > long for me.
> >
> > Any hints why this takes so long ?
> 
> Coastline processing on openstreetmapdata.com is stuck for more than
> a month now, mostly because a lot of back and forth with tagging of
> large lakes as coastline.
> 
> For information: to avoid major disruptions of map rendering due to
> data errors the coastline is not updated if there are larger changes
> in the geometry compared to the last time it was successfully
> processed.  Any addition or removal of a lake with coastline tag will
> require manual intervention and we do not have the time to manually
> check the data every day because some mapper somewhere wants to
> scratch an itch and decides to tag a lake outline with
> natural=coastline.
> 

Thanks for the information! I added this data to
http://wiki.openstreetmap.org/wiki/Coastline#Rendering_in_Standard_tile_layer

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

Re: [OSM-dev] changes in coastline are not rendered

[Stephan Knauss]

On 09.02.2016 11:21, Oleksiy Muzalyev wrote:

On the other hand, I am in doubt, - perhaps, people invested a lot of
time and labor in clicking these hundreds and hundreds of nodes, to make
a nice looking map, and I am not sure if I am doing the right thing with
the tool SHIFT+Y (Simplify Way). Maybe this excessive number of nodes is
negligible for the database and rendering?


This is the reason I suggest against using the simplify functionality. 
Just because some detail level is not to your liking you sort of "tell 
off" those mappers who invested a lot of time putting that details in 
the first place when deleting it.


There are special situations where it can be useful, but in case of 
"hand-drawn" data mostly it is fine to go forward with a handful of 
additional nodes. And don't worry about the size of the data. Those few 
nodes don't do much harm (we have 4 billions already).


Stephan


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

Re: [OSM-dev] changes in coastline are not rendered

[Oleksiy Muzalyev]

On 08/02/16 18:51, Gerd Petermann wrote:


Hi,


pleasse see this way:

http://www.openstreetmap.org/way/396163254

It was changed more than 3 days ago and the change is not rendered.

I understand that coastline ways are special, but that seems too long 
for me.


Any hints why this takes so long ?


ciao,

Gerd



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

Hi Gerd,

This part of the coastline of 3.3 km consists from 238 nodes. It is not 
too much yet. Sometimes I meet a small lake which could be seven hundred 
nodes.


In JOSM there is a tool SHIFT+Y (Simplify Way). After Simplify Way the 
same 3.3 km would be just 102 nodes.


I did not change this particular coastline. But usually when I see too 
many nodes (in my opinion) for a way in JOSM, I make SHIFT+Y and then 
add some more nodes to adjust the shape. I do not know if it is the 
right way, but I think that too large number of nodes could be a heavy 
load for the database and for the rendering program.


On the other hand, I am in doubt, - perhaps, people invested a lot of 
time and labor in clicking these hundreds and hundreds of nodes, to make 
a nice looking map, and I am not sure if I am doing the right thing with 
the tool SHIFT+Y (Simplify Way). Maybe this excessive number of nodes is 
negligible for the database and rendering?


Still this tool, SHIFT+Y (Simplify Way), exists. And it also could be 
that a large quantity of nodes is created automatically by some image 
recognition AI program, or from a GPS trace, and a user was just not 
aware of this tool.


With best regards,
Oleksiy
___
dev mailing list
dev@openstreetmap.org
https://lists.openstreetmap.org/listinfo/dev

[OSM-dev] changes in coastline are not rendered

[Gerd Petermann]

Hi,


pleasse see this way:

http://www.openstreetmap.org/way/396163254


It was changed more than 3 days ago and the change is not rendered.

I understand that coastline ways are special, but that seems too long for me.

Any hints why this takes so long ?


ciao,

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

Re: [OSM-dev] changes in coastline are not rendered

[Christoph Hormann]

On Monday 08 February 2016, Gerd Petermann wrote:
>
> It was changed more than 3 days ago and the change is not rendered.
>
> I understand that coastline ways are special, but that seems too long
> for me.
>
> Any hints why this takes so long ?

Coastline processing on openstreetmapdata.com is stuck for more than a 
month now, mostly because a lot of back and forth with tagging of large 
lakes as coastline.

For information: to avoid major disruptions of map rendering due to data 
errors the coastline is not updated if there are larger changes in the 
geometry compared to the last time it was successfully processed.  Any 
addition or removal of a lake with coastline tag will require manual 
intervention and we do not have the time to manually check the data 
every day because some mapper somewhere wants to scratch an itch and 
decides to tag a lake outline with natural=coastline.

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

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

Re: [OSM-dev] changes in coastline are not rendered

[Jochen Topf]

On Mo, Feb 08, 2016 at 05:51:52 +, Gerd Petermann wrote:
> pleasse see this way:
> 
> http://www.openstreetmap.org/way/396163254
> 
> 
> It was changed more than 3 days ago and the change is not rendered.
> 
> I understand that coastline ways are special, but that seems too long for me.
> 
> Any hints why this takes so long ?

Because the update process didn't produce new files for over a month. You can
see this here: http://openstreetmapdata.com/data/land-polygons (look for "Last
update" in the Download section).

This happens when the changes to the coastlines are larger than some cut-off
which can mean that the coastlines are so badly broken that an update could
lead to some large scale problems. It can also mean that the update process
isn't doing its job. Mostly it means that I didn't have the time to look into
it recently.

Jochen
-- 
Jochen Topf  joc...@remote.org  http://www.jochentopf.com/  +49-351-31778688

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

Re: [OSM-dev] changes in coastline are not rendered

[Gmail]

That's a particular itch, but hey, among the thousands of each month mappers, 
there's a lot of inches.
Why not render anyway these lakes or freeze this object ?
Yves

Le 8 février 2016 20:20:39 UTC+01:00, Christoph Hormann  
a écrit :
>On Monday 08 February 2016, Gerd Petermann wrote:
>>
>> It was changed more than 3 days ago and the change is not rendered.
>>
>> I understand that coastline ways are special, but that seems too long
>> for me.
>>
>> Any hints why this takes so long ?
>
>Coastline processing on openstreetmapdata.com is stuck for more than a 
>month now, mostly because a lot of back and forth with tagging of large
>
>lakes as coastline.
>
>For information: to avoid major disruptions of map rendering due to
>data 
>errors the coastline is not updated if there are larger changes in the 
>geometry compared to the last time it was successfully processed.  Any 
>addition or removal of a lake with coastline tag will require manual 
>intervention and we do not have the time to manually check the data 
>every day because some mapper somewhere wants to scratch an itch and 
>decides to tag a lake outline with natural=coastline.
>
>-- 
>Christoph Hormann
>http://www.imagico.de/
>
>___
>dev mailing list
>dev@openstreetmap.org
>https://lists.openstreetmap.org/listinfo/dev

-- 
Envoyé de mon téléphone Android avec K-9 Mail. Excusez la brièveté.___
dev mailing list
dev@openstreetmap.org
https://lists.openstreetmap.org/listinfo/dev