[gdal-dev] Off-topic: speaking of viewsheds....

[Tamas Szekeres]

That looks very nice.

Best regards,

Tamas


Scott <public at postholer.com> ezt írta (időpont: 2023. júl. 7., P, 21:28):

> The following viewsheds were created with GDAL, one tif for every tenth
> of a mile along the 2,650 mile Pacific Crest Trail. Stitched together
> with ffmpeg:
>
> https://youtu.be/tmY27ZIVfpA
>
>
> On 7/7/23 12:17, Tamas Szekeres wrote:
> > Benoît,
> >
> > As far a I can understand - depending on the elevation model actually
> > used - you may get different results when changing the observer and the
> > target height or the observer location. I'm not sure how it would be
> > different if you set the target height specifically to the observer and
> > the observer height to the target height.
> >
> > Best regards,
> >
> > Tamas
> >
> >
> >
> >
> > Benoît DesRochers <Benoit.DesRochers2 at usherbrooke.ca
> > <mailto:Benoit.DesRochers2 at usherbrooke.ca>> ezt írta (időpont: 2023.
> > júl. 7., P, 19:21):
> >
> >     Hello there,
> >
> >     Long story short, I'm trying to generate a viewshed for every cell
> >     in a raster and add them all up to get a new raster that would
> >     represent how many pixels can be seen from every cell. It takes a
> >     while, but it works!
> >
> >     The problem is that I'm using non-default observer and target height
> >     values (2m observer and 0.5m target) and the results are
> >     significantly different when I invert them (Use the target height as
> >     the observer and the observer as the target height). From what I
> >     understand, most viewshed algorithms don't compute sightlines for
> >     every cell but use a reference plane instead and I'm thinking that
> >     might be where the problem comes from but I'm not sure.
> >
> >     Am I doing something wrong or is that an expected outcome?
> >
> >     Thanks,
> >     Benoît
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