Re: [Tagging] Satellite visibility of archaeological sites

[Marc Gemis]

On Tue, Aug 23, 2016 at 4:27 PM, Bjoern Hassler  wrote:
> So - when I review an object (with no source information provided in the
> tags), and can clearly see it on bing, then would it not be useful to add
> this information to the tags, as a verification? We don't know how it was
> originally added, but the satellite view verifies this

As Tom Pfeiifer already indicated in this thread, for this type of
meta information, you also have to look at the history of the object.
When you do that, you'll see the changeset comments and tags which can
also provide valuable information on the source(s) that were used to
map a feature.

Also, in many places Bing is not providing the best or more recent
imagery, so what is the value to add
"double_checked_with_Bing2012"-tag when more recent imagery from
another provider is available ?

regards

m

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Re: [Tagging] Satellite visibility of archaeological sites

[Martin Koppenhoefer]

please also note that there is orthoimagery from the PCN available for the 
whole of Italy. This is typically better aligned than Bing.
More info here: http://wiki.openstreetmap.org/wiki/WikiProject_Italy/PCN


Cheers,
Martin 


sent from a phone
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Re: [Tagging] Satellite visibility of archaeological sites

[Bjoern Hassler]

Hi Martin,

I am planning to review the objects systematically, and sometimes the
tagging doesn't give much information. Also, as we know, sometimes an
object is added, but the accuracy may not be that high.

So - when I review an object (with no source information provided in the
tags), and can clearly see it on bing, then would it not be useful to add
this information to the tags, as a verification? We don't know how it was
originally added, but the satellite view verifies this.

(For the objects in question, as they are outdoors towers, and as long as
they have reasonable preservation, they are very clearly visible. I
appreciate the earlier comment that it's not possible to validate arbitrary
archaeological sites like that.)

Bjoern

On 23 August 2016 at 14:45, Martin Koppenhoefer 
wrote:

>
>
> sent from a phone
>
> > Il giorno 23 ago 2016, alle ore 14:02, Bjoern Hassler <
> bjohas...@gmail.com> ha scritto:
> >
> > Strictly speaking, bing may not have been the source, as the data may
> come from a ground survey. But would it be reasonable to add "source=bing"
> if the structure is visible on bing? I suppose "verified:bing2012" may be
> clearer, and avoid confusion?
>
>
> any ground survey is much more reliable than an assessment from remote,
> that's why I would put survey in the source tag when I did perform a
> survey. Maybe I just don't get the point why you would add bing tags for a
> site where you have been to. What is the scope?
>
>
> cheers,
> Martin
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Re: [Tagging] Satellite visibility of archaeological sites

[Martin Koppenhoefer]

sent from a phone

> Il giorno 23 ago 2016, alle ore 14:02, Bjoern Hassler  
> ha scritto:
> 
> Strictly speaking, bing may not have been the source, as the data may come 
> from a ground survey. But would it be reasonable to add "source=bing" if the 
> structure is visible on bing? I suppose "verified:bing2012" may be clearer, 
> and avoid confusion?


any ground survey is much more reliable than an assessment from remote, that's 
why I would put survey in the source tag when I did perform a survey. Maybe I 
just don't get the point why you would add bing tags for a site where you have 
been to. What is the scope?


cheers,
Martin 
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Re: [Tagging] Satellite visibility of archaeological sites

[Tom Pfeifer]

Bjoern Hassler wrote on 2016/08/23 14:02:

Hi Martin, hi Marc,

thanks for the response. I suppose another way of looking at it would be to say 
that the site's existence is verifiable from satellite images. Is there a tag 
for that? It could always be added to the note tag, but a structured tag may be 
better. E.g.
"visible:bing2012=1" or "verified:bing2012=1".

Alternatively maybe "source=bing' would also be ok? Strictly speaking, bing may not have 
been the source, as the data may come from a ground survey. But would it be reasonable to add 
"source=bing" if the structure is visible on bing? I suppose
"verified:bing2012" may be clearer, and avoid confusion?

Btw. I'm not proposing a new tag, just seeing whether there is an existing tag 
I can use.


I prefer nowadays to keep track of those activities in the changeset comment 
and the changeset source field.
Putting it on each object clutters it with redundant information, and the first 
mapper verifies the shape,
the next the height and the next the colour, so in the end you don't know 
anymore which action it refers
to, and people might use different layers for mapping/verification.

I only use source, source:geometry, source:name tags on the object if it is a 
method different from the
surroundings, such as the new road not yet visible in aerial imagery, with 
source=gps-trace, or a new building with
source=visual estimation.

tom


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Re: [Tagging] Satellite visibility of archaeological sites

[Stefano]

2016-08-23 13:42 GMT+02:00 Bjoern Hassler :

> Hi all,
>
> how would you tag whether an archaeological site is visible on satellite
> images?
>
> Sardinia has several 1,000 large megalithic stone towers (nuraghe), about
> 600 of which are in OSM. However, they have different states of
> preservation. Some are clearly visible on the satellite image (with
> extensive structures present), but others aren't (and there probably isn't
> much remaining).
>
> This doesn't necessarily indicate their preservation - some are covered by
> forest. So a tag like "preservation" may not be easy to add unless you do a
> ground survey.
>
> However, I'd like to add something like "visibility", indicating whether
> the site is clearly visible from a satellite image (and may thus be worth
> visiting).
>
> What do you think? What tag should I use?
>

Probably you could use tourism = attraction for the most important (Su
Nuraxi, Nuraghe Losa, and so on, perhaps the ones mantained by someone?).
I never had the possibility to further extend the tagging, but the nuraghes
differ by period and by shape (single tower towards castle).

See this for the tagging (I discussed it some years ago with the italian
community) http://wiki.openstreetmap.org/wiki/IT:Glossario_OSM#Nuraghe

Here's my map of them (manually updated)
http://nuraghe.org/map.html#8/40.097/9.124



> Bjoern
>
>
Regards,
Stefano


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Re: [Tagging] Satellite visibility of archaeological sites

[Bjoern Hassler]

I guess I am looking for something like
- http://wiki.openstreetmap.org/wiki/Key:survey:date
- http://wiki.openstreetmap.org/wiki/Key:check_date

but for satellite image cross-check (unlike survey:date, which is for
verification in person).

Bjoern

On 23 August 2016 at 13:02, Bjoern Hassler  wrote:

> Hi Martin, hi Marc,
>
> thanks for the response. I suppose another way of looking at it would be
> to say that the site's existence is verifiable from satellite images. Is
> there a tag for that? It could always be added to the note tag, but a
> structured tag may be better. E.g. "visible:bing2012=1" or
> "verified:bing2012=1".
>
> Alternatively maybe "source=bing' would also be ok? Strictly speaking,
> bing may not have been the source, as the data may come from a ground
> survey. But would it be reasonable to add "source=bing" if the structure is
> visible on bing? I suppose "verified:bing2012" may be clearer, and avoid
> confusion?
>
> Btw. I'm not proposing a new tag, just seeing whether there is an existing
> tag I can use.
>
> Bjoern
>
> On 23 August 2016 at 12:57, Marc Zoutendijk 
> wrote:
>
>>
>> > Op 23 aug. 2016, om 13:42 heeft Bjoern Hassler 
>> het volgende geschreven:
>> >
>> > […]
>>
>> > However, I'd like to add something like "visibility", indicating
>> whether the site is clearly visible from a satellite image (and may thus be
>> worth visiting).
>> >
>> > What do you think? What tag should I use?
>>
>> Satellite images come in various degrees of resolution and hence the
>> visibility tag would have to account for that. Because those sites may not
>> be visible at all on different areal images.
>>
>> And “being worth a vist” can easily be set with one of the tourism=*
>> solutions.
>>
>> Marc.
>>
>>
>>
>>
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>
>
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Re: [Tagging] Satellite visibility of archaeological sites

[Bjoern Hassler]

Hi Martin, hi Marc,

thanks for the response. I suppose another way of looking at it would be to
say that the site's existence is verifiable from satellite images. Is there
a tag for that? It could always be added to the note tag, but a structured
tag may be better. E.g. "visible:bing2012=1" or "verified:bing2012=1".

Alternatively maybe "source=bing' would also be ok? Strictly speaking, bing
may not have been the source, as the data may come from a ground survey.
But would it be reasonable to add "source=bing" if the structure is visible
on bing? I suppose "verified:bing2012" may be clearer, and avoid confusion?

Btw. I'm not proposing a new tag, just seeing whether there is an existing
tag I can use.

Bjoern

On 23 August 2016 at 12:57, Marc Zoutendijk  wrote:

>
> > Op 23 aug. 2016, om 13:42 heeft Bjoern Hassler 
> het volgende geschreven:
> >
> > […]
>
> > However, I'd like to add something like "visibility", indicating whether
> the site is clearly visible from a satellite image (and may thus be worth
> visiting).
> >
> > What do you think? What tag should I use?
>
> Satellite images come in various degrees of resolution and hence the
> visibility tag would have to account for that. Because those sites may not
> be visible at all on different areal images.
>
> And “being worth a vist” can easily be set with one of the tourism=*
> solutions.
>
> Marc.
>
>
>
>
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Re: [Tagging] Satellite visibility of archaeological sites

[Marc Zoutendijk]

> Op 23 aug. 2016, om 13:42 heeft Bjoern Hassler  het 
> volgende geschreven:
> 
> […]

> However, I'd like to add something like "visibility", indicating whether the 
> site is clearly visible from a satellite image (and may thus be worth 
> visiting).
> 
> What do you think? What tag should I use?

Satellite images come in various degrees of resolution and hence the visibility 
tag would have to account for that. Because those sites may not be visible at 
all on different areal images.

And “being worth a vist” can easily be set with one of the tourism=* solutions.

Marc.




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Re: [Tagging] Satellite visibility of archaeological sites

[Martin Koppenhoefer]

sent from a phone

> Il giorno 23 ago 2016, alle ore 13:42, Bjoern Hassler  
> ha scritto:
> 
> However, I'd like to add something like "visibility", indicating whether the 
> site is clearly visible from a satellite image (and may thus be worth 
> visiting).
> 
> What do you think? What tag should I use?


I don't think there is a strong relationship between visibility on aerial 
imagery and worthiness of a visit, e.g. some sites are underground or covered 
by trees or protective roofs, and there are other features that determine the 
interestingness of a site than pure size/extent.

If I encountered a tag "visibility" I would expect it to be the visibility on 
the ground, not from aerial imagery. 


cheers,
Martin 
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[Tagging] Satellite visibility of archaeological sites

[Bjoern Hassler]

Hi all,

how would you tag whether an archaeological site is visible on satellite
images?

Sardinia has several 1,000 large megalithic stone towers (nuraghe), about
600 of which are in OSM. However, they have different states of
preservation. Some are clearly visible on the satellite image (with
extensive structures present), but others aren't (and there probably isn't
much remaining).

This doesn't necessarily indicate their preservation - some are covered by
forest. So a tag like "preservation" may not be easy to add unless you do a
ground survey.

However, I'd like to add something like "visibility", indicating whether
the site is clearly visible from a satellite image (and may thus be worth
visiting).

What do you think? What tag should I use?
Bjoern
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