HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

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HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

Bjoern Hassler
Hi all,

just to follow up on the buildings discussion - it seems that it's not likely that node-buildings will be rendered in the standard cartography, see https://github.com/gravitystorm/openstreetmap-carto/issues/806.

However, I think there is a case for rendering node-buildings in the HOT cartography? I'll file a suggestion here: https://github.com/hotosm/HDM-CartoCSS

Bjoern

On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
On 05/22/2017 01:44 PM, john whelan wrote:

> consider and it is a major part of engineering.  No matter what compression
> system is used four nodes will always take up four times the space as one
> node.  Maybe not with .7z compression looking for strings in the long lat
> but its a good rule of thumb.  Again OSM is now running the largest
> database known in whatever it is running in, I forget the name.  It's

  OSM uses PostgreSQL with the postgis and hstore extensions. I run it
locally to save on bandwidth latency, plus it works offline too cause
connectivity is poor around here. Mobile bandwidth is getting better all
the time all over the planet though. Adding data to OSM is better to be
done the way most others do it than worrying about bandwidth.

  Looking into a few OSM files, I see <node> used as a building that
hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
enough for most people trying to find someplace. For a building that
actually has it's dimensions mapped, then it's a <way>, with references
to each <node>. It depends what type of info you want from your map.
When generating a display map, a <node> won't appear as a building,
it'll just be a cute icon. If you want to see a whole building shape, it
needs to be a <way>. Some buildings have both.

        - rob -

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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

Andrew Buck
The real solution is to "upgrade" these nodes into properly mapped
buildings with a way.  We really should be discouraging people mapping
as nodes like this as it is largely a waste of time since someone has to
map it as a way later on anyway and when they do they either need to
delete the existing nodes or merge them into the buildings to preserve
history (but also taking much longer).

Adding renderings to maps only encourages people to take the easy way
out in the short term and create more bad data.  We should not encourage
this and should be actively trying to fix the nodes already in the
database.  I have done this on a few occasions and have probably knocked
out a few thousand of them, but unless we get serious about cleaning
them up we will end up with more and more of them.

Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.

-AndrewBuck


On 05/25/2017 04:09 AM, Bjoern Hassler wrote:

> Hi all,
>
> just to follow up on the buildings discussion - it seems that it's not
> likely that node-buildings will be rendered in the standard cartography,
> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>
> However, I think there is a case for rendering node-buildings in the HOT
> cartography? I'll file a suggestion here: https://github.com/
> hotosm/HDM-CartoCSS.
>
> Bjoern
>
> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>
>> On 05/22/2017 01:44 PM, john whelan wrote:
>>
>>> consider and it is a major part of engineering.  No matter what
>> compression
>>> system is used four nodes will always take up four times the space as one
>>> node.  Maybe not with .7z compression looking for strings in the long lat
>>> but its a good rule of thumb.  Again OSM is now running the largest
>>> database known in whatever it is running in, I forget the name.  It's
>>
>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>> locally to save on bandwidth latency, plus it works offline too cause
>> connectivity is poor around here. Mobile bandwidth is getting better all
>> the time all over the planet though. Adding data to OSM is better to be
>> done the way most others do it than worrying about bandwidth.
>>
>>   Looking into a few OSM files, I see <node> used as a building that
>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>> enough for most people trying to find someplace. For a building that
>> actually has it's dimensions mapped, then it's a <way>, with references
>> to each <node>. It depends what type of info you want from your map.
>> When generating a display map, a <node> won't appear as a building,
>> it'll just be a cute icon. If you want to see a whole building shape, it
>> needs to be a <way>. Some buildings have both.
>>
>>         - rob -
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>
>
>
> _______________________________________________
> HOT mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/hot
>


_______________________________________________
HOT mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/hot

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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

Enock Seth Nyamador
​Absolutely agree with you Andrew.

Support for building tag on nodes should be dropped by now. ​

Best,

- Enock

2017-05-25 15:08 GMT+00:00 Andrew Buck <[hidden email]>:
The real solution is to "upgrade" these nodes into properly mapped
buildings with a way.  We really should be discouraging people mapping
as nodes like this as it is largely a waste of time since someone has to
map it as a way later on anyway and when they do they either need to
delete the existing nodes or merge them into the buildings to preserve
history (but also taking much longer).

Adding renderings to maps only encourages people to take the easy way
out in the short term and create more bad data.  We should not encourage
this and should be actively trying to fix the nodes already in the
database.  I have done this on a few occasions and have probably knocked
out a few thousand of them, but unless we get serious about cleaning
them up we will end up with more and more of them.

Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.

-AndrewBuck


On 05/25/2017 04:09 AM, Bjoern Hassler wrote:
> Hi all,
>
> just to follow up on the buildings discussion - it seems that it's not
> likely that node-buildings will be rendered in the standard cartography,
> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>
> However, I think there is a case for rendering node-buildings in the HOT
> cartography? I'll file a suggestion here: https://github.com/
> hotosm/HDM-CartoCSS.
>
> Bjoern
>
> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>
>> On 05/22/2017 01:44 PM, john whelan wrote:
>>
>>> consider and it is a major part of engineering.  No matter what
>> compression
>>> system is used four nodes will always take up four times the space as one
>>> node.  Maybe not with .7z compression looking for strings in the long lat
>>> but its a good rule of thumb.  Again OSM is now running the largest
>>> database known in whatever it is running in, I forget the name.  It's
>>
>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>> locally to save on bandwidth latency, plus it works offline too cause
>> connectivity is poor around here. Mobile bandwidth is getting better all
>> the time all over the planet though. Adding data to OSM is better to be
>> done the way most others do it than worrying about bandwidth.
>>
>>   Looking into a few OSM files, I see <node> used as a building that
>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>> enough for most people trying to find someplace. For a building that
>> actually has it's dimensions mapped, then it's a <way>, with references
>> to each <node>. It depends what type of info you want from your map.
>> When generating a display map, a <node> won't appear as a building,
>> it'll just be a cute icon. If you want to see a whole building shape, it
>> needs to be a <way>. Some buildings have both.
>>
>>         - rob -
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>
>
>
> _______________________________________________
> HOT mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/hot
>



_______________________________________________
HOT mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/hot



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[hidden email]
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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

john whelan-2
In reply to this post by Andrew Buck
> Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.


I do a lot of validation and clean up on HOT projects and in the areas they map.  I usually check the number of edits a mapper has done and in my experience HOT mappers may map a building three times, they may not square buildings, the buildings might be three times the size they should be, they map them in odd shapes.  I see villages tagged building=residential but its very rare that I see buildings as nodes from HOT mappers. Generally they look at the training guides which describe mapping buildings as ways.

The mappers I have seen using nodes for buildings, typically tagging nodes building=hut, are generally experienced mappers who have used nodes for street numbers in the past often from Europe. When I come across them I generally mention that the HOT convention is to map the outline.

The concerns I do have about mapping buildings as ways are more on the data quality side. I'm currently looking at Malawi and I'm seeing a number of sites where buildings have been mapped multiple times and I've added tags to a few hundred that have been left area=yes.  Some of these are more than a month or two old.

Personally I'd like to see more use of the JOSM building_tool plugin because at the moment there are many areas where you cannot depend on all the buildings having been mapped, mapped just the once or that the area of the building is anywhere near correct.

Cheerio John

On 25 May 2017 at 11:08, Andrew Buck <[hidden email]> wrote:
The real solution is to "upgrade" these nodes into properly mapped
buildings with a way.  We really should be discouraging people mapping
as nodes like this as it is largely a waste of time since someone has to
map it as a way later on anyway and when they do they either need to
delete the existing nodes or merge them into the buildings to preserve
history (but also taking much longer).

Adding renderings to maps only encourages people to take the easy way
out in the short term and create more bad data.  We should not encourage
this and should be actively trying to fix the nodes already in the
database.  I have done this on a few occasions and have probably knocked
out a few thousand of them, but unless we get serious about cleaning
them up we will end up with more and more of them.

Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.

-AndrewBuck


On 05/25/2017 04:09 AM, Bjoern Hassler wrote:
> Hi all,
>
> just to follow up on the buildings discussion - it seems that it's not
> likely that node-buildings will be rendered in the standard cartography,
> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>
> However, I think there is a case for rendering node-buildings in the HOT
> cartography? I'll file a suggestion here: https://github.com/
> hotosm/HDM-CartoCSS.
>
> Bjoern
>
> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>
>> On 05/22/2017 01:44 PM, john whelan wrote:
>>
>>> consider and it is a major part of engineering.  No matter what
>> compression
>>> system is used four nodes will always take up four times the space as one
>>> node.  Maybe not with .7z compression looking for strings in the long lat
>>> but its a good rule of thumb.  Again OSM is now running the largest
>>> database known in whatever it is running in, I forget the name.  It's
>>
>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>> locally to save on bandwidth latency, plus it works offline too cause
>> connectivity is poor around here. Mobile bandwidth is getting better all
>> the time all over the planet though. Adding data to OSM is better to be
>> done the way most others do it than worrying about bandwidth.
>>
>>   Looking into a few OSM files, I see <node> used as a building that
>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>> enough for most people trying to find someplace. For a building that
>> actually has it's dimensions mapped, then it's a <way>, with references
>> to each <node>. It depends what type of info you want from your map.
>> When generating a display map, a <node> won't appear as a building,
>> it'll just be a cute icon. If you want to see a whole building shape, it
>> needs to be a <way>. Some buildings have both.
>>
>>         - rob -
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>
>
>
> _______________________________________________
> HOT mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/hot
>



_______________________________________________
HOT mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/hot



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[hidden email]
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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

Bjoern Hassler
Hi all,

so I don't want to revisit the whole discussion, but here's my view. This isn't a suggestion to change the HOT-default of mapping buildings as way, but just to explain my approach. I've recently mapped about 2,000 node-buildings near Fiwila, Northern Zambia. I checked the OSM wiki, it said node[building] is ok, and so I went ahead. I also mapped a bunch of roads. The reason I did this is because I've previously collaborated with one of the health workers there, who is now in Fiwila, and so I wanted to support their work in he clinic there (where there's very poor mobile signal, people are paid tiny salaries, no mains electricity....).

So we now know the number of houses (as nodes), and the roads for how to get there. From a pragmatic perspective, I think that's ok for our purposes. Here are some considerations:

(1) The node[building=yes] are not rendered in standard carto, HOT carto, nor by maps.me. However, OSMAND displays them as building icons. My preference would for the buildings to be rendered by maps.me and HOT carto. However, I do understand people's concerns. 

(2) Could I have traced these nodes as ways? It took me a while as it stands (as the buildings are spread out over some areas), so I don't think i would have mapped as many if I had traced them. I also think that for our application ("knowing where people are") it's not that relevant.

So what else could I do?

(a) Rather than pasting nodes in the centre of the building, I could have pasted a small 4m by 4m square, either aligning with centre of the building, or even try to paste onto an edge of the building, and just leave them like this (half finished). These would render, but would potentially be considered "mapping for the renderer", so not ideal. However, they would be easier to extend to the proper building outline later (as the tag is on the way already, and one node may be in place already). So maybe that would have been preferable? Are there any strong views against that?

(b) Alternatively, I could have just marked residential areas. I switched to that a bit later just to try it, and perhaps that is the better solution. I.e. "If you cannot map building outlines, just map residential areas instead". Residential areas don't render amazingly, but they do render. However, it doesn't help knowing how many households there are - but perhaps that's ok for us too.

We're also trying to write some JOSM plugins:

(1) A plugin that can take a set of buildings, and create the residential area automatically, as a concave hull. (We'll post soon about this.)

(2) Potentially a plugin assists the user in converting node[building] into way[building]. As John mentioned, I do think the building plugin is really useful, and it seems feasible to add some functionality to it for converting from node[building] into way[building].

Generally speaking, I'm keen on developing tools that can help speed things up, making processes more user friendly, more reliable, etc. More on that soon.

Anyway - just my thoughts on the matter!
Bjoern



On 25 May 2017 at 17:49, john whelan <[hidden email]> wrote:
> Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.


I do a lot of validation and clean up on HOT projects and in the areas they map.  I usually check the number of edits a mapper has done and in my experience HOT mappers may map a building three times, they may not square buildings, the buildings might be three times the size they should be, they map them in odd shapes.  I see villages tagged building=residential but its very rare that I see buildings as nodes from HOT mappers. Generally they look at the training guides which describe mapping buildings as ways.

The mappers I have seen using nodes for buildings, typically tagging nodes building=hut, are generally experienced mappers who have used nodes for street numbers in the past often from Europe. When I come across them I generally mention that the HOT convention is to map the outline.

The concerns I do have about mapping buildings as ways are more on the data quality side. I'm currently looking at Malawi and I'm seeing a number of sites where buildings have been mapped multiple times and I've added tags to a few hundred that have been left area=yes.  Some of these are more than a month or two old.

Personally I'd like to see more use of the JOSM building_tool plugin because at the moment there are many areas where you cannot depend on all the buildings having been mapped, mapped just the once or that the area of the building is anywhere near correct.

Cheerio John

On 25 May 2017 at 11:08, Andrew Buck <[hidden email]> wrote:
The real solution is to "upgrade" these nodes into properly mapped
buildings with a way.  We really should be discouraging people mapping
as nodes like this as it is largely a waste of time since someone has to
map it as a way later on anyway and when they do they either need to
delete the existing nodes or merge them into the buildings to preserve
history (but also taking much longer).

Adding renderings to maps only encourages people to take the easy way
out in the short term and create more bad data.  We should not encourage
this and should be actively trying to fix the nodes already in the
database.  I have done this on a few occasions and have probably knocked
out a few thousand of them, but unless we get serious about cleaning
them up we will end up with more and more of them.

Buildings as nodes is not a recognized way of mapping them that has
broad support.  Almost without exception the only people doing this are
newbie HOT mappers who don't know the correct procedure.  So this is a
mistake that should be fixed, just like non-square buildings or
unconnected roads.

-AndrewBuck


On 05/25/2017 04:09 AM, Bjoern Hassler wrote:
> Hi all,
>
> just to follow up on the buildings discussion - it seems that it's not
> likely that node-buildings will be rendered in the standard cartography,
> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>
> However, I think there is a case for rendering node-buildings in the HOT
> cartography? I'll file a suggestion here: https://github.com/
> hotosm/HDM-CartoCSS.
>
> Bjoern
>
> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>
>> On 05/22/2017 01:44 PM, john whelan wrote:
>>
>>> consider and it is a major part of engineering.  No matter what
>> compression
>>> system is used four nodes will always take up four times the space as one
>>> node.  Maybe not with .7z compression looking for strings in the long lat
>>> but its a good rule of thumb.  Again OSM is now running the largest
>>> database known in whatever it is running in, I forget the name.  It's
>>
>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>> locally to save on bandwidth latency, plus it works offline too cause
>> connectivity is poor around here. Mobile bandwidth is getting better all
>> the time all over the planet though. Adding data to OSM is better to be
>> done the way most others do it than worrying about bandwidth.
>>
>>   Looking into a few OSM files, I see <node> used as a building that
>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>> enough for most people trying to find someplace. For a building that
>> actually has it's dimensions mapped, then it's a <way>, with references
>> to each <node>. It depends what type of info you want from your map.
>> When generating a display map, a <node> won't appear as a building,
>> it'll just be a cute icon. If you want to see a whole building shape, it
>> needs to be a <way>. Some buildings have both.
>>
>>         - rob -
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>
>
>
> _______________________________________________
> HOT mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/hot
>



_______________________________________________
HOT mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/hot



_______________________________________________
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[hidden email]
https://lists.openstreetmap.org/listinfo/hot



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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

Andrew Buck
As you say, you looked on the wiki and it does list building nodes as
acceptable.  Mapping them this way is not wrong, it is just far from
optimal.

Regarding the plugins for josm, I don't know that either of these are
really needed.  Residential areas as convex hulls can be easily made in
qgis and then imported into OSM if that is desired, however this was
done by someone a while back (during the Ebola activation in west
africa) and for most areas the result was OK but it still took a lot of
manual work to merge them in anyway, so just drawing them by hand is
almost faster anyway.

For the second one, to convert nodes to areas for buildings you don't
need a plugin as there is already the replace geometry tool in josm
which does exactly this.  If you are doing many hundreds, then the
conflation tools plugin works in conjunction with replace geometry to
match nodes to buildings and then "replace geometry" on each match
automatically.  So a plugin is not really needed.

So to summarize my overall points.  Mapping as a node is not wrong, but
I would rather see someone spend an hour mapping a few hundred buildings
as areas rather than a few thousand as nodes, since the nodes will have
to be mapped as areas eventually anyway.  So as far as I see it it is
just a wasted hour of mapping.  Remember, we are mapping the whole world
and we aim for completeness.  We will achieve this, so why do something
half way, just do it fully the first time so it doesn't have to be done
again.

-AndrewBuck



On 05/25/2017 02:07 PM, Bjoern Hassler wrote:

> Hi all,
>
> so I don't want to revisit the whole discussion, but here's my view. This
> isn't a suggestion to change the HOT-default of mapping buildings as way,
> but just to explain my approach. I've recently mapped about 2,000
> node-buildings near Fiwila, Northern Zambia. I checked the OSM wiki, it
> said node[building] is ok, and so I went ahead. I also mapped a bunch of
> roads. The reason I did this is because I've previously collaborated with
> one of the health workers there, who is now in Fiwila, and so I wanted to
> support their work in he clinic there (where there's very poor mobile
> signal, people are paid tiny salaries, no mains electricity....).
>
> So we now know the number of houses (as nodes), and the roads for how to
> get there. From a pragmatic perspective, I think that's ok for our
> purposes. Here are some considerations:
>
> (1) The node[building=yes] are not rendered in standard carto, HOT carto,
> nor by maps.me. However, OSMAND displays them as building icons. My
> preference would for the buildings to be rendered by maps.me and HOT carto.
> However, I do understand people's concerns.
>
> (2) Could I have traced these nodes as ways? It took me a while as it
> stands (as the buildings are spread out over some areas), so I don't think
> i would have mapped as many if I had traced them. I also think that for our
> application ("knowing where people are") it's not that relevant.
>
> So what else could I do?
>
> (a) Rather than pasting nodes in the centre of the building, I could have
> pasted a small 4m by 4m square, either aligning with centre of the
> building, or even try to paste onto an edge of the building, and just leave
> them like this (half finished). These would render, but would potentially
> be considered "mapping for the renderer", so not ideal. However, they would
> be easier to extend to the proper building outline later (as the tag is on
> the way already, and one node may be in place already). So maybe that would
> have been preferable? Are there any strong views against that?
>
> (b) Alternatively, I could have just marked residential areas. I switched
> to that a bit later just to try it, and perhaps that is the better
> solution. I.e. "If you cannot map building outlines, just map residential
> areas instead". Residential areas don't render amazingly, but they do
> render. However, it doesn't help knowing how many households there are -
> but perhaps that's ok for us too.
>
> We're also trying to write some JOSM plugins:
>
> (1) A plugin that can take a set of buildings, and create the residential
> area automatically, as a concave hull. (We'll post soon about this.)
>
> (2) Potentially a plugin assists the user in converting node[building] into
> way[building]. As John mentioned, I do think the building plugin is really
> useful, and it seems feasible to add some functionality to it for
> converting from node[building] into way[building].
>
> Generally speaking, I'm keen on developing tools that can help speed things
> up, making processes more user friendly, more reliable, etc. More on that
> soon.
>
> Anyway - just my thoughts on the matter!
> Bjoern
>
>
>
> On 25 May 2017 at 17:49, john whelan <[hidden email]> wrote:
>
>>> Buildings as nodes is not a recognized way of mapping them that has
>> broad support.  Almost without exception the only people doing this are
>> newbie HOT mappers who don't know the correct procedure.  So this is a
>> mistake that should be fixed, just like non-square buildings or
>> unconnected roads.
>>
>> I do a lot of validation and clean up on HOT projects and in the areas
>> they map.  I usually check the number of edits a mapper has done and in my
>> experience HOT mappers may map a building three times, they may not square
>> buildings, the buildings might be three times the size they should be, they
>> map them in odd shapes.  I see villages tagged building=residential but its
>> very rare that I see buildings as nodes from HOT mappers. Generally they
>> look at the training guides which describe mapping buildings as ways.
>>
>> The mappers I have seen using nodes for buildings, typically tagging nodes
>> building=hut, are generally experienced mappers who have used nodes for
>> street numbers in the past often from Europe. When I come across them I
>> generally mention that the HOT convention is to map the outline.
>>
>> The concerns I do have about mapping buildings as ways are more on the
>> data quality side. I'm currently looking at Malawi and I'm seeing a number
>> of sites where buildings have been mapped multiple times and I've added
>> tags to a few hundred that have been left area=yes.  Some of these are more
>> than a month or two old.
>>
>> Personally I'd like to see more use of the JOSM building_tool plugin
>> because at the moment there are many areas where you cannot depend on all
>> the buildings having been mapped, mapped just the once or that the area of
>> the building is anywhere near correct.
>>
>> Cheerio John
>>
>> On 25 May 2017 at 11:08, Andrew Buck <[hidden email]> wrote:
>>
>>> The real solution is to "upgrade" these nodes into properly mapped
>>> buildings with a way.  We really should be discouraging people mapping
>>> as nodes like this as it is largely a waste of time since someone has to
>>> map it as a way later on anyway and when they do they either need to
>>> delete the existing nodes or merge them into the buildings to preserve
>>> history (but also taking much longer).
>>>
>>> Adding renderings to maps only encourages people to take the easy way
>>> out in the short term and create more bad data.  We should not encourage
>>> this and should be actively trying to fix the nodes already in the
>>> database.  I have done this on a few occasions and have probably knocked
>>> out a few thousand of them, but unless we get serious about cleaning
>>> them up we will end up with more and more of them.
>>>
>>> Buildings as nodes is not a recognized way of mapping them that has
>>> broad support.  Almost without exception the only people doing this are
>>> newbie HOT mappers who don't know the correct procedure.  So this is a
>>> mistake that should be fixed, just like non-square buildings or
>>> unconnected roads.
>>>
>>> -AndrewBuck
>>>
>>>
>>> On 05/25/2017 04:09 AM, Bjoern Hassler wrote:
>>>> Hi all,
>>>>
>>>> just to follow up on the buildings discussion - it seems that it's not
>>>> likely that node-buildings will be rendered in the standard cartography,
>>>> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>>>>
>>>> However, I think there is a case for rendering node-buildings in the HOT
>>>> cartography? I'll file a suggestion here: https://github.com/
>>>> hotosm/HDM-CartoCSS.
>>>>
>>>> Bjoern
>>>>
>>>> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>>>>
>>>>> On 05/22/2017 01:44 PM, john whelan wrote:
>>>>>
>>>>>> consider and it is a major part of engineering.  No matter what
>>>>> compression
>>>>>> system is used four nodes will always take up four times the space as
>>> one
>>>>>> node.  Maybe not with .7z compression looking for strings in the long
>>> lat
>>>>>> but its a good rule of thumb.  Again OSM is now running the largest
>>>>>> database known in whatever it is running in, I forget the name.  It's
>>>>>
>>>>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>>>>> locally to save on bandwidth latency, plus it works offline too cause
>>>>> connectivity is poor around here. Mobile bandwidth is getting better
>>> all
>>>>> the time all over the planet though. Adding data to OSM is better to be
>>>>> done the way most others do it than worrying about bandwidth.
>>>>>
>>>>>   Looking into a few OSM files, I see <node> used as a building that
>>>>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>>>>> enough for most people trying to find someplace. For a building that
>>>>> actually has it's dimensions mapped, then it's a <way>, with references
>>>>> to each <node>. It depends what type of info you want from your map.
>>>>> When generating a display map, a <node> won't appear as a building,
>>>>> it'll just be a cute icon. If you want to see a whole building shape,
>>> it
>>>>> needs to be a <way>. Some buildings have both.
>>>>>
>>>>>         - rob -
>>>>>
>>>>> _______________________________________________
>>>>> HOT mailing list
>>>>> [hidden email]
>>>>> https://lists.openstreetmap.org/listinfo/hot
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> HOT mailing list
>>>> [hidden email]
>>>> https://lists.openstreetmap.org/listinfo/hot
>>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> HOT mailing list
>>> [hidden email]
>>> https://lists.openstreetmap.org/listinfo/hot
>>>
>>>
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>


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Re: HOT carto, Re: Buildings and residential areas: Buldings as nodes (Q1)

john whelan-2
>So to summarize my overall points.  Mapping as a node is not wrong, but
I would rather see someone spend an hour mapping a few hundred buildings
as areas rather than a few thousand as nodes, since the nodes will have
to be mapped as areas eventually anyway.  So as far as I see it it is
just a wasted hour of mapping.  Remember, we are mapping the whole world
and we aim for completeness.  We will achieve this, so why do something
half way, just do it fully the first time so it doesn't have to be done
again.


But from the HOT point of view they are much more interested in supporting people on the ground in the immediate time frame.  If you look at the imagery over time villages sometimes move. 

HOT and OSM don't have quite the same objectives.  HOT very much uses a subset of the OSM available options and tags.  It takes a much more standardised approach.

There are definitely NGOs on the HOT side who would prefer a few thousand accurate nodes to a few hundred buildings mapped as ways but with the JOSM building tool plugin at three clicks of the mouse it doesn't take much longer to map the building than it does to cut and paste a node. 

We have over a thousand HOT projects open at the moment, some have been open for five years.  We have limited mapping resources certainly not enough to meet the demands / requests from the NGOs.  Given the amount of effort needed to clean up the buildings mapped as ways would mapping as nodes make the best use of the available mapping resources given that the JOSM building_tool plugin is considered too complicated for new mappers?

Cheerio John

On 25 May 2017 at 17:49, Andrew Buck <[hidden email]> wrote:
As you say, you looked on the wiki and it does list building nodes as
acceptable.  Mapping them this way is not wrong, it is just far from
optimal.

Regarding the plugins for josm, I don't know that either of these are
really needed.  Residential areas as convex hulls can be easily made in
qgis and then imported into OSM if that is desired, however this was
done by someone a while back (during the Ebola activation in west
africa) and for most areas the result was OK but it still took a lot of
manual work to merge them in anyway, so just drawing them by hand is
almost faster anyway.

For the second one, to convert nodes to areas for buildings you don't
need a plugin as there is already the replace geometry tool in josm
which does exactly this.  If you are doing many hundreds, then the
conflation tools plugin works in conjunction with replace geometry to
match nodes to buildings and then "replace geometry" on each match
automatically.  So a plugin is not really needed.

So to summarize my overall points.  Mapping as a node is not wrong, but
I would rather see someone spend an hour mapping a few hundred buildings
as areas rather than a few thousand as nodes, since the nodes will have
to be mapped as areas eventually anyway.  So as far as I see it it is
just a wasted hour of mapping.  Remember, we are mapping the whole world
and we aim for completeness.  We will achieve this, so why do something
half way, just do it fully the first time so it doesn't have to be done
again.

-AndrewBuck



On 05/25/2017 02:07 PM, Bjoern Hassler wrote:
> Hi all,
>
> so I don't want to revisit the whole discussion, but here's my view. This
> isn't a suggestion to change the HOT-default of mapping buildings as way,
> but just to explain my approach. I've recently mapped about 2,000
> node-buildings near Fiwila, Northern Zambia. I checked the OSM wiki, it
> said node[building] is ok, and so I went ahead. I also mapped a bunch of
> roads. The reason I did this is because I've previously collaborated with
> one of the health workers there, who is now in Fiwila, and so I wanted to
> support their work in he clinic there (where there's very poor mobile
> signal, people are paid tiny salaries, no mains electricity....).
>
> So we now know the number of houses (as nodes), and the roads for how to
> get there. From a pragmatic perspective, I think that's ok for our
> purposes. Here are some considerations:
>
> (1) The node[building=yes] are not rendered in standard carto, HOT carto,
> nor by maps.me. However, OSMAND displays them as building icons. My
> preference would for the buildings to be rendered by maps.me and HOT carto.
> However, I do understand people's concerns.
>
> (2) Could I have traced these nodes as ways? It took me a while as it
> stands (as the buildings are spread out over some areas), so I don't think
> i would have mapped as many if I had traced them. I also think that for our
> application ("knowing where people are") it's not that relevant.
>
> So what else could I do?
>
> (a) Rather than pasting nodes in the centre of the building, I could have
> pasted a small 4m by 4m square, either aligning with centre of the
> building, or even try to paste onto an edge of the building, and just leave
> them like this (half finished). These would render, but would potentially
> be considered "mapping for the renderer", so not ideal. However, they would
> be easier to extend to the proper building outline later (as the tag is on
> the way already, and one node may be in place already). So maybe that would
> have been preferable? Are there any strong views against that?
>
> (b) Alternatively, I could have just marked residential areas. I switched
> to that a bit later just to try it, and perhaps that is the better
> solution. I.e. "If you cannot map building outlines, just map residential
> areas instead". Residential areas don't render amazingly, but they do
> render. However, it doesn't help knowing how many households there are -
> but perhaps that's ok for us too.
>
> We're also trying to write some JOSM plugins:
>
> (1) A plugin that can take a set of buildings, and create the residential
> area automatically, as a concave hull. (We'll post soon about this.)
>
> (2) Potentially a plugin assists the user in converting node[building] into
> way[building]. As John mentioned, I do think the building plugin is really
> useful, and it seems feasible to add some functionality to it for
> converting from node[building] into way[building].
>
> Generally speaking, I'm keen on developing tools that can help speed things
> up, making processes more user friendly, more reliable, etc. More on that
> soon.
>
> Anyway - just my thoughts on the matter!
> Bjoern
>
>
>
> On 25 May 2017 at 17:49, john whelan <[hidden email]> wrote:
>
>>> Buildings as nodes is not a recognized way of mapping them that has
>> broad support.  Almost without exception the only people doing this are
>> newbie HOT mappers who don't know the correct procedure.  So this is a
>> mistake that should be fixed, just like non-square buildings or
>> unconnected roads.
>>
>> I do a lot of validation and clean up on HOT projects and in the areas
>> they map.  I usually check the number of edits a mapper has done and in my
>> experience HOT mappers may map a building three times, they may not square
>> buildings, the buildings might be three times the size they should be, they
>> map them in odd shapes.  I see villages tagged building=residential but its
>> very rare that I see buildings as nodes from HOT mappers. Generally they
>> look at the training guides which describe mapping buildings as ways.
>>
>> The mappers I have seen using nodes for buildings, typically tagging nodes
>> building=hut, are generally experienced mappers who have used nodes for
>> street numbers in the past often from Europe. When I come across them I
>> generally mention that the HOT convention is to map the outline.
>>
>> The concerns I do have about mapping buildings as ways are more on the
>> data quality side. I'm currently looking at Malawi and I'm seeing a number
>> of sites where buildings have been mapped multiple times and I've added
>> tags to a few hundred that have been left area=yes.  Some of these are more
>> than a month or two old.
>>
>> Personally I'd like to see more use of the JOSM building_tool plugin
>> because at the moment there are many areas where you cannot depend on all
>> the buildings having been mapped, mapped just the once or that the area of
>> the building is anywhere near correct.
>>
>> Cheerio John
>>
>> On 25 May 2017 at 11:08, Andrew Buck <[hidden email]> wrote:
>>
>>> The real solution is to "upgrade" these nodes into properly mapped
>>> buildings with a way.  We really should be discouraging people mapping
>>> as nodes like this as it is largely a waste of time since someone has to
>>> map it as a way later on anyway and when they do they either need to
>>> delete the existing nodes or merge them into the buildings to preserve
>>> history (but also taking much longer).
>>>
>>> Adding renderings to maps only encourages people to take the easy way
>>> out in the short term and create more bad data.  We should not encourage
>>> this and should be actively trying to fix the nodes already in the
>>> database.  I have done this on a few occasions and have probably knocked
>>> out a few thousand of them, but unless we get serious about cleaning
>>> them up we will end up with more and more of them.
>>>
>>> Buildings as nodes is not a recognized way of mapping them that has
>>> broad support.  Almost without exception the only people doing this are
>>> newbie HOT mappers who don't know the correct procedure.  So this is a
>>> mistake that should be fixed, just like non-square buildings or
>>> unconnected roads.
>>>
>>> -AndrewBuck
>>>
>>>
>>> On 05/25/2017 04:09 AM, Bjoern Hassler wrote:
>>>> Hi all,
>>>>
>>>> just to follow up on the buildings discussion - it seems that it's not
>>>> likely that node-buildings will be rendered in the standard cartography,
>>>> see https://github.com/gravitystorm/openstreetmap-carto/issues/806.
>>>>
>>>> However, I think there is a case for rendering node-buildings in the HOT
>>>> cartography? I'll file a suggestion here: https://github.com/
>>>> hotosm/HDM-CartoCSS.
>>>>
>>>> Bjoern
>>>>
>>>> On 23 May 2017 at 04:54, Rob Savoye <[hidden email]> wrote:
>>>>
>>>>> On 05/22/2017 01:44 PM, john whelan wrote:
>>>>>
>>>>>> consider and it is a major part of engineering.  No matter what
>>>>> compression
>>>>>> system is used four nodes will always take up four times the space as
>>> one
>>>>>> node.  Maybe not with .7z compression looking for strings in the long
>>> lat
>>>>>> but its a good rule of thumb.  Again OSM is now running the largest
>>>>>> database known in whatever it is running in, I forget the name.  It's
>>>>>
>>>>>   OSM uses PostgreSQL with the postgis and hstore extensions. I run it
>>>>> locally to save on bandwidth latency, plus it works offline too cause
>>>>> connectivity is poor around here. Mobile bandwidth is getting better
>>> all
>>>>> the time all over the planet though. Adding data to OSM is better to be
>>>>> done the way most others do it than worrying about bandwidth.
>>>>>
>>>>>   Looking into a few OSM files, I see <node> used as a building that
>>>>> hasn't been mapped as a polygon, ie.. just a waypoint. That's useful
>>>>> enough for most people trying to find someplace. For a building that
>>>>> actually has it's dimensions mapped, then it's a <way>, with references
>>>>> to each <node>. It depends what type of info you want from your map.
>>>>> When generating a display map, a <node> won't appear as a building,
>>>>> it'll just be a cute icon. If you want to see a whole building shape,
>>> it
>>>>> needs to be a <way>. Some buildings have both.
>>>>>
>>>>>         - rob -
>>>>>
>>>>> _______________________________________________
>>>>> HOT mailing list
>>>>> [hidden email]
>>>>> https://lists.openstreetmap.org/listinfo/hot
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> HOT mailing list
>>>> [hidden email]
>>>> https://lists.openstreetmap.org/listinfo/hot
>>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> HOT mailing list
>>> [hidden email]
>>> https://lists.openstreetmap.org/listinfo/hot
>>>
>>>
>>
>> _______________________________________________
>> HOT mailing list
>> [hidden email]
>> https://lists.openstreetmap.org/listinfo/hot
>>
>>
>




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