> I imagine any proposed import would run into similar issues, particularly
>since the> imagery in Nepal is likely not as good as the multispectral+lidar
>that
> vtcraghead had.
Yes, but also consider other ways of using this LIDAR data.
LIDAR, with aerial imagery, could be another useful source for manual editing.
Imagine a tasking manager job, that included lidar derived tiles, in order to
map rough building height.
-Mikel
* Mikel Maron * +14152835207 @mikel s:mikelmaron
>________________________________
> From: Paul Norman <[email protected]>
>To: 'maning sambale' <[email protected]>; 'Ryan Sommerville'
><[email protected]>
>Cc: [email protected]
>Sent: Friday, February 8, 2013 2:38 AM
>Subject: Re: [HOT] Advice tracing footprints with poor imagery in Kathmandu,
>Nepal
>
>> From: maning sambale [mailto:[email protected]]
>> Subject: Re: [HOT] Advice tracing footprints with poor imagery in
>> Kathmandu, Nepal
>>
>> There are opensource tools that can extract features from hires imagery,
>> an example is GRASS, see this sample process (ignore the subjectline :))
>>
>> http://lists.osgeo.org/pipermail/grass-user/2007-August/040808.html
>>
>> But this requires, that you have direct access to the imagery (which
>> isn't legally allowed with Bing)
>>
>> Another option for small areas is to try balloon/kite mapping:
>>
>> http://grassrootsmapping.org/
>>
>> In my experience, the most effective way is by manually tracing in JOSM
>> (no computer algorithm can do what a human can see, at least not
>> yet) and of course ground validation.
>
>The last time someone proposed importing automatically generated building
>outlines[1] the consensus was against it. They used multispectral imagery
>and LIDAR coverage and there were still significant concerns about the
>quality. One of the basic problems with automatic building detection is that
>buildings tend to consist of right angles but automatic detection methods
>tend be better with irregularly shaped areas like tree coverage. I imagine
>any proposed import would run into similar issues, particularly since the
>imagery in Nepal is likely not as good as the multispectral+lidar that
>vtcraghead had.
>
>[1]: http://lists.openstreetmap.org/pipermail/imports/2012-March/001267.html
>
>
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