[Qgis-user] Interpolation

[Michael Treglia]

Just to clarify, the goal is to to effectively map the ridges and furrows?
Or am I missing something?

If there's high resolution orthoimagery, you could try to use standard
image classification techniques to classify the ridges and furrows. They're
visible enough on Google Earth that I bet it's doable if you can get good
imagery, depending on exactly what you need... For that site you suggested,
looks like about 0.5 m from furrow to furrow, so definitely requires high
resolution - if your area is the same, that's tough and imagery might be
more expensive, but if you can get a sample to try it out with, it might be
cheaper than doing LiDAR

I like Alex's point of using Kites (or Balloons) for high res imagery.

Hope that helps
mike

On Thu, Sep 18, 2014 at 1:21 PM, Alex Mandel <tech_dev at wildintellect.com>
wrote:

> 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.
> >
> >
> > _______________________________________________
> > Qgis-user mailing list
> > Qgis-user at lists.osgeo.org<mailto:Qgis-user at lists.osgeo.org>
> > http://lists.osgeo.org/mailman/listinfo/qgis-user
> >
> >
> >
> > --
> > Andy Harfoot
> >
> > GeoData Institute
> > University of Southampton
> > Southampton
> > SO17 1BJ
> >
> > Tel:  +44 (0)23 8059 2719
> > Fax:  +44 (0)23 8059 2849
> >
> > www.geodata.soton.ac.uk<http://www.geodata.soton.ac.uk>
> >
> >
> >
> >
> > _______________________________________________
> > Qgis-user mailing list
> > Qgis-user at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/qgis-user
> >
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20140918/144a1a02/attachment.html>