[GRASSLIST:1779] Re: i.ortho.photo on osx
neteler at itc.it
Mon Nov 17 11:22:25 EST 2003
On Mon, Nov 17, 2003 at 08:13:41AM -0800, Ian Macmillan wrote:
> Markus, thanks for the response. I do have a dem which covers the entire
> photo area. It is a little larger in fact, is that a problem?
That's perfect. It *should* be larger.
> Should I crop it
> so that it is the same size as the photo in area? The dem is at 10m
> resolution, just like I want the projected orthophoto to be. I made the DEM
> with s.surf.rst from a 30m dem, doesn't seem like that should make any
> difference from a "normal" dem. In any case the elevation range is only ~540
> meters. Is this too much? What is the biggest elevation range that you have
> gotten to work?
I cannot tell you right now, have to check first.
> The r.univar report for the dem is here:
> Number of cells: 432276
> Minimum: 579.7407226562
> Maximum: 1119.2756347656
> Range: 539.535
> Arithmetic mean: 775.406
> Variance: 17639.4
> Standard deviation: 132.813
> Variation coefficient: 17.1282 %
> Thanks a bunch, ian
> Quoting Markus Neteler <neteler at itc.it>:
> > On Sat, Nov 15, 2003 at 12:38:05PM -0800, Ian Macmillan wrote:
> > > Hi all, anyone out there successfully used i.ortho.photo on max os x
> > (jaguar)?
> > > I have been having bad luck with it. I consistently get a weird tiling
> > effect
> > > with highly distorted images. A good example can be found here.
> > >
> > > www.uweb.ucsb.edu/~ian_macmillan/calico.tif
> > >
> > > I have a previous post that explains exactly what I did to get this image
> > > (1702). As far as I can tell, I have done everything by the book.
> > Anybody
> > > have any advice?
> > >
> > > Thanks a bunch
> > >
> > > -ian
> > Ian,
> > a similar problem we also face (on Linux, so it's a bug in the i.ortho.photo
> > library).
> > Some things to check:
> > - do you have a DEM which covers the area of the target orthophoto,
> > all at the same resolution?
> > - what's the elevation difference in that area
> > (r.univar tells you min and max etc)
> > We have the impression, that the algorithm is somewhat unstable in regions
> > with a large elevation range.
> > Markus Neteler
> Ian MacMillan
> Geological Sciences-UCSB
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