[gdal-dev] Generating Viewsheds without Using Sightlines

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[gdal-dev] Generating Viewsheds without Using Sightlines

Tamas Szekeres
Hi,

I've implemented a viewshed algorithm a while ago, by utilizing a modified version of the algorithm published at https://www.asprs.org/wp-content/uploads/pers/2000journal/january/2000_jan_87-90.pdf

With this approach, it was crucial to provide a fast real-time option for the viewshed calculation on relatively large raster DEMs by using only a small memory footprint.

The implementation can be found here:


Does it make sense to spend some more effort and incorporate this approach in GDAL officially?

Best regards,

Tamas

 

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Re: Generating Viewsheds without Using Sightlines

Even Rouault-2
On lundi 30 septembre 2019 20:10:38 CEST Tamas Szekeres wrote:

> Hi,
>
> I've implemented a viewshed algorithm a while ago, by utilizing a modified
> version of the algorithm published at
> https://www.asprs.org/wp-content/uploads/pers/2000journal/january/2000_jan_8
> 7-90.pdf
>
> With this approach, it was crucial to provide a fast real-time option for
> the viewshed calculation on relatively large raster DEMs by using only a
> small memory footprint.
>
> The implementation can be found here:
>
> https://github.com/szekerest/gdal/blob/viewshed/gdal/alg/viewshed.cpp
> https://github.com/szekerest/gdal/blob/viewshed/gdal/apps/gdal_viewshed.cpp
>
> Does it make sense to spend some more effort and incorporate this approach
> in GDAL officially?

Sounds useful to me !
(old memories of having implement line-of-sight based intervisibility
algorithm in a past life !)

Even

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Re: Generating Viewsheds without Using Sightlines

Eli Adam
On Mon, Sep 30, 2019 at 11:54 AM Even Rouault
<[hidden email]> wrote:

>
> On lundi 30 septembre 2019 20:10:38 CEST Tamas Szekeres wrote:
> > Hi,
> >
> > I've implemented a viewshed algorithm a while ago, by utilizing a modified
> > version of the algorithm published at
> > https://www.asprs.org/wp-content/uploads/pers/2000journal/january/2000_jan_8
> > 7-90.pdf
> >
> > With this approach, it was crucial to provide a fast real-time option for
> > the viewshed calculation on relatively large raster DEMs by using only a
> > small memory footprint.
> >
> > The implementation can be found here:
> >
> > https://github.com/szekerest/gdal/blob/viewshed/gdal/alg/viewshed.cpp
> > https://github.com/szekerest/gdal/blob/viewshed/gdal/apps/gdal_viewshed.cpp
> >
> > Does it make sense to spend some more effort and incorporate this approach
> > in GDAL officially?
>
> Sounds useful to me !
> (old memories of having implement line-of-sight based intervisibility
> algorithm in a past life !)

Gdaldem (although it has a different history) has an assortment of DEM
based utilities, https://gdal.org/programs/gdaldem.html  I'm not sure
if it would make sense there or elsewhere.  It would be a useful tool.

Best regards, Eli



>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
> _______________________________________________
> gdal-dev mailing list
> [hidden email]
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
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Re: Generating Viewsheds without Using Sightlines

Tamas Szekeres
As far as I see, the size of the output raster is equal to the input size with the gdaldem utility set.
With the viewshed approach, the size of the output raster is calculated according to the provided parameters (ie. the observer location and maxdistance), however it is a good idea to allow the user customize the output format is some way.

Best regards,

Tamas


Eli Adam <[hidden email]> ezt írta (időpont: 2019. szept. 30., H, 21:35):
On Mon, Sep 30, 2019 at 11:54 AM Even Rouault
<[hidden email]> wrote:
>
> On lundi 30 septembre 2019 20:10:38 CEST Tamas Szekeres wrote:
> > Hi,
> >
> > I've implemented a viewshed algorithm a while ago, by utilizing a modified
> > version of the algorithm published at
> > https://www.asprs.org/wp-content/uploads/pers/2000journal/january/2000_jan_8
> > 7-90.pdf
> >
> > With this approach, it was crucial to provide a fast real-time option for
> > the viewshed calculation on relatively large raster DEMs by using only a
> > small memory footprint.
> >
> > The implementation can be found here:
> >
> > https://github.com/szekerest/gdal/blob/viewshed/gdal/alg/viewshed.cpp
> > https://github.com/szekerest/gdal/blob/viewshed/gdal/apps/gdal_viewshed.cpp
> >
> > Does it make sense to spend some more effort and incorporate this approach
> > in GDAL officially?
>
> Sounds useful to me !
> (old memories of having implement line-of-sight based intervisibility
> algorithm in a past life !)

Gdaldem (although it has a different history) has an assortment of DEM
based utilities, https://gdal.org/programs/gdaldem.html  I'm not sure
if it would make sense there or elsewhere.  It would be a useful tool.

Best regards, Eli



>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
> _______________________________________________
> gdal-dev mailing list
> [hidden email]
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
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