Re: [Talk-us] understanding administrative boundary relations

2015-09-05 Thread Ray Kiddy 
On Fri, 4 Sep 2015 21:40:57 -0400
Richard Welty  wrote:

> On 9/4/15 5:09 PM, Ray Kiddy wrote:
> > So, there is nothing that a relation brings to the table that a way
> > does not? I mean, it is clear that for the purposes of drawing, they
> > are the same. But then are they really just the same?
> i don't know about the current style, but in the past there has been
> an issue
> where a way was contained in a relation, and both the way and the
> relation had the same admin boundary tagging. the stylesheet of 1-2
> years ago would draw the admin boundary twice.
> 
> i haven't checked to see if this problem has been fixed or  not. the
> correct answer is to only tag the relation and remove any duplicate
> tagging from the way, especially because the way may be in multiple
> relations and with different admin levels in the different relations.
> 
> richard
> 

Yes, that is what I would do. It would just be what would make sense.

thanx - ray

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Re: [Talk-us] understanding administrative boundary relations

2015-09-04 Thread Ray Kiddy 
On Fri, 4 Sep 2015 07:06:33 +0200
Marc Gemis  wrote:

> On Fri, Sep 4, 2015 at 3:56 AM, Ray Kiddy  wrote:
> 
> > It has occurred to me that there will probably need to be a
> > "boundary watcher" tool, which can let an interested group know
> > about it when a boundary gets broken in some way. And I have
> > started playing with the python libraries for accessing OSM data
> > with this in mind.
> >
> 
> There is a German team that does this. They maintain the website
> https://osm.wno-edv-service.de/boundaries/ from which you can
> download all administrative boundaries in a number of formats.
> They also have a website with all missing (or broken) administrative
> boundaries:
> https://osm.wno-edv-service.de/index.php/projekte/internationale-administrative-grenzen/missing-boundaries
>  (in German)
> 
> regards

Others had mentioned the site to me. When I was looking at it, things
did not make so much sense, but I can see it now.

Strangely, I am finding that some of the cities in California _are_ in
the system, but as ways and not as relations. This seems odd, but we
will see.

And, actually, it looks as though the missing-boundaries pages are in
both German and English. So that will help. Other parts are still in
German, but I can deal.

I will check with them about some of this.

thanx - ray

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Re: [Talk-us] understanding administrative boundary relations

2015-09-04 Thread Toby Murray 
On Fri, Sep 4, 2015 at 1:37 PM, Ray Kiddy  wrote:
>
> Strangely, I am finding that some of the cities in California _are_ in
> the system, but as ways and not as relations. This seems odd, but we
> will see.

Well the primary reason to use relations in boundaries is to reduce
duplication. So if two cities share a border, the same way can be used
in both relations. Sometimes people even use roads or streams or other
physical ways as part of boundary relations. I personally usually
avoid this because I like having boundary relations completely
separate from other things so that they are easier to update in the
future. So for a city that is not part of a metro area with adjoining
cities, it is perfectly fine to just used a closed way instead of a
relation for the boundary. At the end of the day, both ways and
relations generally get turned into either linestrings (if linear) or
multipolygons (if closed) in things like a postgis database or a
shapefile.

Toby

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Re: [Talk-us] understanding administrative boundary relations

2015-09-04 Thread Ray Kiddy 
On Fri, 4 Sep 2015 14:11:26 -0500
Toby Murray  wrote:

> On Fri, Sep 4, 2015 at 1:37 PM, Ray Kiddy  wrote:
> >
> > Strangely, I am finding that some of the cities in California _are_
> > in the system, but as ways and not as relations. This seems odd,
> > but we will see.
> 
> Well the primary reason to use relations in boundaries is to reduce
> duplication. So if two cities share a border, the same way can be used
> in both relations. Sometimes people even use roads or streams or other
> physical ways as part of boundary relations. I personally usually
> avoid this because I like having boundary relations completely
> separate from other things so that they are easier to update in the
> future. So for a city that is not part of a metro area with adjoining
> cities, it is perfectly fine to just used a closed way instead of a
> relation for the boundary. At the end of the day, both ways and
> relations generally get turned into either linestrings (if linear) or
> multipolygons (if closed) in things like a postgis database or a
> shapefile.
> 
> Toby
> 

So, there is nothing that a relation brings to the table that a way
does not? I mean, it is clear that for the purposes of drawing, they
are the same. But then are they really just the same?

I am tempted to try to add relations for these that refer to the ways,
moving the associated data appropriately, but then I like to do things
like re-normalizing databases and it is sometimes not such a good
idea

So, I will believe you if you say that ways are just aliases for
relations. Is this the case?

- ray

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Re: [Talk-us] understanding administrative boundary relations

2015-09-04 Thread Richard Welty 
On 9/4/15 5:09 PM, Ray Kiddy wrote:
> So, there is nothing that a relation brings to the table that a way
> does not? I mean, it is clear that for the purposes of drawing, they
> are the same. But then are they really just the same?
i don't know about the current style, but in the past there has been an
issue
where a way was contained in a relation, and both the way and the relation
had the same admin boundary tagging. the stylesheet of 1-2 years ago
would draw the admin boundary twice.

i haven't checked to see if this problem has been fixed or  not. the correct
answer is to only tag the relation and remove any duplicate tagging from
the way, especially because the way may be in multiple relations and with
different admin levels in the different relations.

richard

-- 
rwe...@averillpark.net
 Averill Park Networking - GIS & IT Consulting
 OpenStreetMap - PostgreSQL - Linux
 Java - Web Applications - Search




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[Talk-us] understanding administrative boundary relations

2015-09-03 Thread Ray Kiddy 

Hello -

I am on a quest to learn more about how administrative boundaries can
be managed as relations. I have a bit of experience with these
things, but I am discovering the limitations of my knowledge also.
Which was the point, actually.

I would like to be able to suggest that governmental entities could
manage their district geo data with OSM. I am interested in seeing why
this does not work now and what can be done. Well, and it would be
interesting to find out why so few cities in California actually seem
to have a relation. Or perhaps I am missing it.

I know that TIGER data was imported into OSM, but I am seeing some
disconnects. To be precise:

Using QGIS, I can load the vector files (SHP) from the following as two
different layers:

ftp://ftp2.census.gov/geo/tiger/TIGER2015/ELSD/tl_2015_06_elsd.zip
ftp://ftp2.census.gov/geo/tiger/TIGER2015/EDGES/tl_2015_06085_edges.zip

Using JOSM, I can see the "Sunnyvale East Channel":

https://www.openstreetmap.org/#map=19/37.364537971457935/-122.02110206207291

I cannot see how to get the id of this way from JOSM and its tag info
seems to be:

boat=no
intermittent=yes
name=Sunnyvale East Channel
scvwd:FACILITY=2026
scvwd:ROUTEID=20260
waterway=drain

And in QGIS, I can see the same feature (removing empty TIGER fields):

wkt_geomLINESTRING
-122.02132171 37.364089025
-122.0209720001465 37.364640178
-122.019929475 37.366293634
-122.0196390001217 37.366754025
STATEFP 6
COUNTYFP85
TLID618169892
TFIDL   229597201
TFIDR   230278901
MTFCC   P0001
HYDROFLGN
RAILFLG N
ROADFLG N
OLFFLG  N
EXTTYP  N
GCSEFLG N
OFFSETL N
OFFSETR N
TNIDF   39083667
TNIDT   409312163

But there seems to be no connection between the feature in OSM and the
TIGER data. So, TIGER data was used to define new features? But perhaps
TIGER id data was not merged onto existing features?

I am certainly not seeing "tiger:tlid"="618169892" associated with this
object in OSM anywhere.

So, if I want to give the Sunnyvale District the relation that defines
its boundaries, I cannot use TIGER data to find those lines? Or rather,
I must use the TIGER data and find the line in OSM and set up the
connection myself?

Ok Any other suggestions?

thanx - ray


ps:

My early stumblings are in my diary:

http://www.openstreetmap.org/user/rayKiddy/diary

Please excuse any ignorance on my part. I know a bit about the GIS
practices of the state of California. I have a very small bit of
experience with Santa Clara County. I have a smidgen of knowledge about
the city of Sunnyvale. And I have more exposure to the Sunnyvale
Elementary School District, having once been on the Board. And I
develop database software and am interested in mapping applications.



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Re: [Talk-us] understanding administrative boundary relations

2015-09-03 Thread Toby Murray 
The area you linked to has no boundary data in OSM. You don't state
this in your email but by pulling up the TIGER shapefile, it looks
like you are wanting school district boundaries? I see one runs
through the area you linked to, in the shapefile. School districts
were not imported into OSM. The only things that were imported from
TIGER is roads, state, county and city boundaries.

Administrative boundaries in OSM have always been a tricky subject.
OSM thrives on information that can be verified by someone standing on
the ground, looking around and seeing something that can be put into
the map. Administrative boundaries are (usually) not that way. They
are imaginary lines drawn on the map. Sometimes they follow physical
features but often they don't. So the only source to verify or update
them is to go back to the imaginary line drawer and ask for an update.

Because of this, I think boundaries in OSM tend to deteriorate in
quality quicker than other features. Sometimes people modify a way
that is part of a boundary relation and don't realize that they are
affecting the boundary. I have done a lot of work fixing up boundaries
(mostly county) across the country and there are definitely a million
ways to break them.

If you want an example of an admin boundary in OSM, here is the
Sunnyvale city boundary relation:
https://www.openstreetmap.org/relation/112145

Toby


On Thu, Sep 3, 2015 at 5:40 PM, Ray Kiddy  wrote:
>
> Hello -
>
> I am on a quest to learn more about how administrative boundaries can
> be managed as relations. I have a bit of experience with these
> things, but I am discovering the limitations of my knowledge also.
> Which was the point, actually.
>
> I would like to be able to suggest that governmental entities could
> manage their district geo data with OSM. I am interested in seeing why
> this does not work now and what can be done. Well, and it would be
> interesting to find out why so few cities in California actually seem
> to have a relation. Or perhaps I am missing it.
>
> I know that TIGER data was imported into OSM, but I am seeing some
> disconnects. To be precise:
>
> Using QGIS, I can load the vector files (SHP) from the following as two
> different layers:
>
> ftp://ftp2.census.gov/geo/tiger/TIGER2015/ELSD/tl_2015_06_elsd.zip
> ftp://ftp2.census.gov/geo/tiger/TIGER2015/EDGES/tl_2015_06085_edges.zip
>
> Using JOSM, I can see the "Sunnyvale East Channel":
>
> https://www.openstreetmap.org/#map=19/37.364537971457935/-122.02110206207291
>
> I cannot see how to get the id of this way from JOSM and its tag info
> seems to be:
>
> boat=no
> intermittent=yes
> name=Sunnyvale East Channel
> scvwd:FACILITY=2026
> scvwd:ROUTEID=20260
> waterway=drain
>
> And in QGIS, I can see the same feature (removing empty TIGER fields):
>
> wkt_geomLINESTRING
> -122.02132171 37.364089025
> -122.0209720001465 37.364640178
> -122.019929475 37.366293634
> -122.0196390001217 37.366754025
> STATEFP 6
> COUNTYFP85
> TLID618169892
> TFIDL   229597201
> TFIDR   230278901
> MTFCC   P0001
> HYDROFLGN
> RAILFLG N
> ROADFLG N
> OLFFLG  N
> EXTTYP  N
> GCSEFLG N
> OFFSETL N
> OFFSETR N
> TNIDF   39083667
> TNIDT   409312163
>
> But there seems to be no connection between the feature in OSM and the
> TIGER data. So, TIGER data was used to define new features? But perhaps
> TIGER id data was not merged onto existing features?
>
> I am certainly not seeing "tiger:tlid"="618169892" associated with this
> object in OSM anywhere.
>
> So, if I want to give the Sunnyvale District the relation that defines
> its boundaries, I cannot use TIGER data to find those lines? Or rather,
> I must use the TIGER data and find the line in OSM and set up the
> connection myself?
>
> Ok Any other suggestions?
>
> thanx - ray
>
>
> ps:
>
> My early stumblings are in my diary:
>
> http://www.openstreetmap.org/user/rayKiddy/diary
>
> Please excuse any ignorance on my part. I know a bit about the GIS
> practices of the state of California. I have a very small bit of
> experience with Santa Clara County. I have a smidgen of knowledge about
> the city of Sunnyvale. And I have more exposure to the Sunnyvale
> Elementary School District, having once been on the Board. And I
> develop database software and am interested in mapping applications.
>
>
>
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Re: [Talk-us] understanding administrative boundary relations

2015-09-03 Thread Marc Gemis 
On Fri, Sep 4, 2015 at 3:56 AM, Ray Kiddy  wrote:

> It has occurred to me that there will probably need to be a "boundary
> watcher" tool, which can let an interested group know about it when a
> boundary gets broken in some way. And I have started playing with the
> python libraries for accessing OSM data with this in mind.
>

There is a German team that does this. They maintain the website
https://osm.wno-edv-service.de/boundaries/ from which you can download all
administrative boundaries in a number of formats.
They also have a website with all missing (or broken) administrative
boundaries:
https://osm.wno-edv-service.de/index.php/projekte/internationale-administrative-grenzen/missing-boundaries
 (in German)

regards
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Re: [Talk-us] understanding administrative boundary relations

2015-09-03 Thread Ray Kiddy 
On Thu, 3 Sep 2015 18:51:50 -0500
Toby Murray  wrote:

> The area you linked to has no boundary data in OSM. You don't state
> this in your email but by pulling up the TIGER shapefile, it looks
> like you are wanting school district boundaries? I see one runs
> through the area you linked to, in the shapefile. School districts
> were not imported into OSM. The only things that were imported from
> TIGER is roads, state, county and city boundaries.

Interesting. There are lots of linear features that are not roads or
the boundaries mentioned. The water feature I described is one.

And, yes, I am looking at school district boundaries right now. But
really, the question is about any other set of relations that are
supposed to tile the map. For example, I knew about Sunnyvale's
relation, which you mention below, but there are over 350 cities in
California and there do not seem to be that many relations, or I cannot
find them (despite some banging of my head against OverPass), or both.

I was hoping that city boundaries would follow conventions like
"admin_level"="8", "place"="city" and so on. More fool I. Most of these
"rules" definitely seem to be honored in the breach.

> Administrative boundaries in OSM have always been a tricky subject.
> OSM thrives on information that can be verified by someone standing on
> the ground, looking around and seeing something that can be put into
> the map. Administrative boundaries are (usually) not that way. They
> are imaginary lines drawn on the map. Sometimes they follow physical
> features but often they don't. So the only source to verify or update
> them is to go back to the imaginary line drawer and ask for an update.

I had not heard this perspective. I am not sure what to say, other than
that though it is a "tricky" subject, it is not really something that
can be ignored. Too many things in real life depend on these
boundaries.

> Because of this, I think boundaries in OSM tend to deteriorate in
> quality quicker than other features. Sometimes people modify a way
> that is part of a boundary relation and don't realize that they are
> affecting the boundary. I have done a lot of work fixing up boundaries
> (mostly county) across the country and there are definitely a million
> ways to break them.

It has occurred to me that there will probably need to be a "boundary
watcher" tool, which can let an interested group know about it when a
boundary gets broken in some way. And I have started playing with the
python libraries for accessing OSM data with this in mind.

> 
> If you want an example of an admin boundary in OSM, here is the
> Sunnyvale city boundary relation:
> https://www.openstreetmap.org/relation/112145
> 

Yep. Knew about that one. Here is the table I am keeping my "meta-data"
list of relations that I am interested in:

mysql> select * from osm_relations;
++--+--+-+
| pk | url  | name  
   | place   |
++--+--+-+
|  1 | http://www.openstreetmap.org/relation/112145 | Sunnyvale, CA, USA
   | city|
|  2 | http://www.openstreetmap.org/relation/148838 | United States of America  
   | country |
|  3 | NULL | Sunnyvale Elementary 
School District | school district |
++--+--+-+

As you can see, the relation for the SESD still needs to be defined.
And there are some others TBD.

- ray


> Toby
> 
> 
> On Thu, Sep 3, 2015 at 5:40 PM, Ray Kiddy  wrote:
> >
> > Hello -
> >
> > I am on a quest to learn more about how administrative boundaries
> > can be managed as relations. I have a bit of experience with these
> > things, but I am discovering the limitations of my knowledge also.
> > Which was the point, actually.
> >
> > I would like to be able to suggest that governmental entities could
> > manage their district geo data with OSM. I am interested in seeing
> > why this does not work now and what can be done. Well, and it would
> > be interesting to find out why so few cities in California actually
> > seem to have a relation. Or perhaps I am missing it.
> >
> > I know that TIGER data was imported into OSM, but I am seeing some
> > disconnects. To be precise:
> >
> > Using QGIS, I can load the vector files (SHP) from the following as
> > two different layers:
> >
> > ftp://ftp2.census.gov/geo/tiger/TIGER2015/ELSD/tl_2015_06_elsd.zip
> > ftp://ftp2.census.gov/geo/tiger/TIGER2015/EDGES/tl_2015_06085_edges.zip
> >
> > Using JOSM, I can see the "Sunnyvale East Channel":
> >
> > https://www.openstreetmap.org/#map=19/37.364537971457935/-122.02110206207291
> >
> > I cannot