Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Warin]

On 19/03/19 11:22, Andy Townsend wrote:

On 18/03/2019 23:41, Warin wrote:


For a chimney that is surrounded by a building  I used the shadow of 
the chimney vs the shadow of the building.


That may be more feasible more of the time where you live than where I 
do!


Point. :)

Some satellite images have cloud cover .. I can usually find another 
satellite image that does not have that cover...


There is some tool on my android phone (named umm swiss army knife?) 
that is supposed to determine height ... I have never used that bit of 
it...


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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Andy Townsend]

On 18/03/2019 23:41, Warin wrote:


For a chimney that is surrounded by a building  I used the shadow of 
the chimney vs the shadow of the building.


That may be more feasible more of the time where you live than where I do!

Best Regards,

Andy



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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Warin]

On 19/03/19 10:13, Andy Townsend wrote:


On 18/03/2019 21:05, Neil Matthews wrote:


P.S. Any suggestions  on how I can measure buildings "on-foot" 
greatly apreciated...



If you can't get hold of one of these*: 
https://www.aols.org/archives/historical-artifacts?page=13 , and if 
you're after the heights of large buildings in a city that you can get 
fairly close to, how about a plastic set-square held horizontal by 
aligning the perpendicular side to a piece of string held down by a 
weight?  The height of the building should be half your distance from 
it.  Or just cheat and count the floors.


Best Regards,

Andy

* turn the mirror through 90 degrees, look through the gap and at the 
reflection of your eye, adjust the weight and read the number off the 
scale


For a chimney that is surrounded by a building  I used the shadow of the 
chimney vs the shadow of the building. Do tag the source:height !  
Someone may be able to do better, if not at least it provides amusement 
for others.


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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Andy Townsend]

On 18/03/2019 21:05, Neil Matthews wrote:


P.S. Any suggestions  on how I can measure buildings "on-foot" greatly 
apreciated...



If you can't get hold of one of these*: 
https://www.aols.org/archives/historical-artifacts?page=13 , and if 
you're after the heights of large buildings in a city that you can get 
fairly close to, how about a plastic set-square held horizontal by 
aligning the perpendicular side to a piece of string held down by a 
weight?  The height of the building should be half your distance from 
it.  Or just cheat and count the floors.


Best Regards,

Andy

* turn the mirror through 90 degrees, look through the gap and at the 
reflection of your eye, adjust the weight and read the number off the scale



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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Neil Matthews]

Thanks for the DEFRA link - has some potential :-)

The first issue I was raising was that for convenience some (commercial)
OSM mappers were using a value like 0.75 per building level (or
something similar) so that their rendering software could deal directly
with OSM data without post-processing it. Effectively a 100 level set of
flats would be marked as building:level=75.

The second issue is how to ensure that height values used for 3D mapping
aren't just being made up (given previous behaviour) - or coming a
source that isn't appropriate for OpenStreetmap.
Unfortunately, I haven't managed to get the editors to cite the data
source they are using for building (part) heights, etc. -- but I do note
that the area isn't mapped by DEFRA lidar!

Cheers,
Neil

P.S. Any suggestions  on how I can measure buildings "on-foot" greatly
apreciated...


On 18/03/2019 15:31, SK53 wrote:
> How very useful; had completely forgotten about this!
>
> However, I don't think that is Neil's issue, which is that
> building:levels should have integer values (or just possibly steps of
> a half). Some 3D renders make assumptions about what a default height
> for a single storey (level) will be. A good example is
> here: https://demo.f4map.com/#lat=52.9755467=-1.2013530=18 (I
> accidentally typed the house number into the building:levels tag).
>
> Jerry
>
> On Mon, 18 Mar 2019 at 15:13, Brian Prangle  > wrote:
>
> Try this site
> 
> :
> origin of building height data is Environment Agency LIDAR data
> under OGL
>
> Regards
>
> Brian
>
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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[SK53]

How very useful; had completely forgotten about this!

However, I don't think that is Neil's issue, which is that building:levels
should have integer values (or just possibly steps of a half). Some 3D
renders make assumptions about what a default height for a single storey
(level) will be. A good example is here:
https://demo.f4map.com/#lat=52.9755467=-1.2013530=18 (I
accidentally typed the house number into the building:levels tag).

Jerry

On Mon, 18 Mar 2019 at 15:13, Brian Prangle  wrote:

> Try this site
> :
> origin of building height data is Environment Agency LIDAR data under OGL
>
> Regards
>
> Brian
>
> On Sat, 16 Mar 2019 at 19:20, Neil Matthews  wrote:
>
>> Anyone mapping in Manchester might want to take a look for strange
>> fractional building:levels.
>>
>> It's possible that some commercial editors found that they got better
>> results with open source 3D renderers by using ~0.75 per building level,
>> rather than the documented value of 1.
>> We recently had a spate of strange edits around Aztec West -- with some
>> 1-level mobile homes being labelled as 1.5 (presumably thought they were
>> a "scaled" two storey house when satellite mapping).
>>
>> On a similar vein, what are acceptable data sources for building:height
>> -- and how far should one ask for proof that these haven't come from a
>> source that would be problematic to OpenStreetmap?
>>
>> Cheers,
>> Neil
>>
>>
>>
>>
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Re: [Talk-GB] Invalid building levels and building (part) height license compatibility

[Brian Prangle]

Try this site
:
origin of building height data is Environment Agency LIDAR data under OGL

Regards

Brian

On Sat, 16 Mar 2019 at 19:20, Neil Matthews  wrote:

> Anyone mapping in Manchester might want to take a look for strange
> fractional building:levels.
>
> It's possible that some commercial editors found that they got better
> results with open source 3D renderers by using ~0.75 per building level,
> rather than the documented value of 1.
> We recently had a spate of strange edits around Aztec West -- with some
> 1-level mobile homes being labelled as 1.5 (presumably thought they were
> a "scaled" two storey house when satellite mapping).
>
> On a similar vein, what are acceptable data sources for building:height
> -- and how far should one ask for proof that these haven't come from a
> source that would be problematic to OpenStreetmap?
>
> Cheers,
> Neil
>
>
>
>
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[Talk-GB] Invalid building levels and building (part) height license compatibility

[Neil Matthews]

Anyone mapping in Manchester might want to take a look for strange
fractional building:levels.

It's possible that some commercial editors found that they got better
results with open source 3D renderers by using ~0.75 per building level,
rather than the documented value of 1.
We recently had a spate of strange edits around Aztec West -- with some
1-level mobile homes being labelled as 1.5 (presumably thought they were
a "scaled" two storey house when satellite mapping).

On a similar vein, what are acceptable data sources for building:height
-- and how far should one ask for proof that these haven't come from a
source that would be problematic to OpenStreetmap?

Cheers,
Neil




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