[Qgis-user] Interpolation

[Alex Mandel]

Yes, that's exactly the use case for Kite/Balloon photography.
See https://sites.google.com/site/mtobiasresearch/diy-remote-sensing-1

We recently tried the OpenDroneMap on some of our photos:
http://smathermather.wordpress.com/2014/09/16/opendronemap-art-and-science/

Thanks,
Alex

On 09/18/2014 11:56 AM, Michael.Dodd wrote:
> Sounds very interesting.
> I am trying to map the ridge and furrow so that I can see how plants are distributed on them.  I have been recording the plants with the high accuracy gps so have these locations to cm level accuracy but not been able to put them on a model of the R&F itself.  If the photography is high enough resolution and taken from low enough the individual plants themselves might show up.
> ________________________________________
> From: Alex Mandel [tech_dev at wildintellect.com]
> Sent: Thursday, September 18, 2014 7:21 PM
> To: Michael.Dodd; Andrew Harfoot; qgis-user at lists.osgeo.org
> Subject: Re: [Qgis-user] Interpolation
> 
> All the rage at http://2014.FOSS4g.org - Structure From Motion.
> Basically using airphotos to build a 3d mesh model of an area with
> classic photogrammetry calculations automated. Photos need not be from
> directly overhead.
> 
> Specifically see the talks by Stephen Mather and Aaron Racicot.
> 
> The open source option are not quite 100% there yet (Stephen's talk on
> OpenDroneMap) but there is a $170 program PhotoScan that's an option
> (See Aaron's talk).
> 
> Thanks,
> Alex
> 
> PS: I use cheap cameras on Kites for sub-centimeter photography.
> 
> On 09/18/2014 10:58 AM, Michael.Dodd wrote:
>> Yes had thought about this and nearly got Leica to test out their latest laser scanner a couple of years ago but land owner was frightened it might cause some kind of damage to the area so it never happened.
>>
>>
>> ________________________________
>> From: Andrew Harfoot [ajph at geodata.soton.ac.uk]
>> Sent: Thursday, September 18, 2014 2:46 PM
>> To: qgis-user at lists.osgeo.org
>> Subject: Re: [Qgis-user] Interpolation
>>
>> Hi Michael,
>>
>> Off the top of my head, but have you looked into a laser scanner mounted on some sort of aerial platform such as a cherry picker? Not sure whether the platform would be stable enough.
>>
>> Alternatively a low level UAV flight may provide a detailed enough DTM through stereo imagery analysis.
>>
>> Cheers,
>>
>> Andy
>>
>> On 18/09/2014 10:43, Michael.Dodd wrote:
>> Any suggestions as to the best way to survey and interpolate ridge and furrow grassland that is not on a flat plane?
>> I have tried various methods without success.
>>
>> The ridge and furrow area that I want to map is about 120mx120m, the ridge and furrow pattern is distinct with about 0.5m or difference between ridge ht and furrow base but the pattern has a slight curve towards one end and the land is not flat.  If you are not sure what ridge and furrow looks like then there is an example at 51.9827, -0.9135, the stripes are clearly visible on the google earth image.
>>
>> Mapping can be done with cm level dgps but does this require many tens of thousands of points to be recorded. Or can fewer points be recorded and qgis interpolation somehow be told to interpolate along the ridge and furrow then fill in the area between them with some sort of curve. The actual curve is also problematic as the ridge top tends to be flattened and not a smooth sine wave.  I don't have good LIDAR of the area but even that resolution may not be good enough.
>>
>> -- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302). The Open University is authorised and regulated by the Financial Conduct Authority.
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>> --
>> Andy Harfoot
>>
>> GeoData Institute
>> University of Southampton
>> Southampton
>> SO17 1BJ
>>
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-- 
Alex Mandel
http://wildintellect.com