Martin,
For HOT Activations in Mali and Congo, I had this experience of detecting where
Bing High Res Imagery is available. This is like a gruyere cheese. To detect
areas, you have to zoom in and cover large areas. This is a tedious work and I
have not find other ways then tracing polygons. The tools you list are not
precise enough to do that very precisely. Some areas are colored red, and when
you zoom in, this becomes green.
If you want to help us and test a better way, I would be pleased. Otherwise,
please do not remove these polygons.
Pierre
>________________________________
> De : Martin Koppenhoefer <dieterdre...@gmail.com>
>À : Stephan Knauss <o...@stephans-server.de>
>Cc : osm <talk@openstreetmap.org>
>Envoyé le : Lundi 1 avril 2013 6h20
>Objet : Re: [OSM-talk] Imagery Boundary?
>
>
>
>
>2013/4/1 Stephan Knauss <o...@stephans-server.de>
>
>Florian Lohoff writes:
>>
>>As they were wrong and nobody cared i deleted them.
>>>
A better way of dealing with updated data in OSM is usually to fix and not to
delete data. Had you considered mailing the users who created the original data
before removing their work?
>>
>
>
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>
>please take a step back: imagery coverage of external providers is not
>geographic "data". I am not saying it is completely useless in cases it
>actually describes the boundaries of imagery coverage in areas with few local
>mappers (because local mappers usually know the boundaries and don't need
>coverage polygons), but when the coverage changes (e.g. gaps get filled,
>coverage gets completed) these polygons really become useless.
>
>
>
>In contrast to eg. underground power lines (seen them mapped in Munich) or TMC
>data or obscure boundaries, this is data which is easy to verify and used in
>the more remote areas of the world.
>>
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>used for what? The only purpose I can imagine is find areas in the editor with
>few data where good imagery enables you to trace more stuff out of this
>imagery. A scope that can be achieved also with external tools like
>http://ant.dev.openstreetmap.org/bingimageanalyzer/ and
>http://mvexel.dev.openstreetmap.org/bing/
>
>
>
>You might not believe it, but there are areas which still have only the
>low-resolution landsat images. Quite often it's the same areas that lack
>mapping of major highways.
>
>
>
>
>sure, but how do coverage boundaries that show that there is no good imagery
>to refine the data help in these cases?
>
>
>
>The imagery boundaries are used to give oversea mappers a hint where areas are
>that can benefit from remote mapping, to complete at least major highways and
>water features.
>>
>
>+1, and that's all these boundaries can achieve, and to achieve this it is
>essential that the coverage is reflecting the actual state.
>
>
>Btw.: how many boundaries shall we tolerate? For every imagery provider and
>every zoom level? I often encountered boundaries that were more or less
>detailed in lower zoom levels but didn't perfectly reflect the situation for
>high zoom levels. When tracing in a remote country it is usually "automatic"
>that you discover the bounds of the good imagery, personally I never needed a
>meta data polygon for this ;-)
>
>
>cheers,
>Martin
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>
>
>
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