[GRASS-dev] [r.sun]

[Ben Hur Pintor]

Thanks for the response. I've seen a lot of literature and uses of r.sun
which is one of the reasons why I chose it as my model aside from the fact
that it's open-source. However, most of the uses are European setting which
I understand since r.sun is based on ESRA. I wanted to see how well r.sun
performs in a more tropical setting and from my initial findings and
studies, it seems to be doing pretty well.

r.sun and r.sunmask both seem to use the SOLPOS algorithm, the SPA (
http://www.nrel.gov/docs/fy08osti/34302.pdf) is a more recent solar
positioning algorithm by NREL and is much more precise than SOLPOS so I
wondered if using SPA instead of SOLPOS might provide better results.

With regards to using LiDAR-derived raster data, my machine can actually
handle it but it just takes a lot of time. I have a 1m resolution LiDAR of
a 500 sq km area (~5GB) and it really just takes a lot of time and disk
space -- specially for horizon rasters. I'm looking into parallel
processing to remedy this issue.

Lastly, I would also like to go into 3D urban solar energy modelling which
is why I asked about v.sun or any other attempts in GRASS to develop a
model for solar radiation received by 3D objects (i.e. buildings including
facades and roofs).

Again, thank you.

On Thu, Apr 28, 2016 at 6:09 PM, Luca Delucchi <lucadeluge at gmail.com> wrote:

> On 28 April 2016 at 06:58, Ben Hur Pintor <bnhr.dev at gmail.com> wrote:
> >
> > Greetings everyone.
> >
>
> Hi,
>
> > I use r.sun for solar radiation modelling in the Philippines. I have a
> few
> > questions and clarifications and I hope you can indulge me:
> >
> > 1. Aside from NCSU-OSGeoREL (whose resources on r.sun I'm very much
> thankful
> > for), are there anyone else out there working on r.sun?
> >
>
> For sure I used r.sun several times, I think als JRC is using it [0]
>
> >
> > 3. I also work with LiDAR and other high resolution data, is it
> advisable to
> > use multi-threading with r.sun?
> >
>
> r.sun use raster as input, if you have high resolution raster data it
> is not a problem if you computer is able to manage it.
> I run r.sun using DEM with 40/30 cm of resolution.
> I think that multi-threading could be used launching several r.sun job
> in different cpu/core
>
> > 4. I'm currently working on Python scripts to compute monthly average
> solar
> > radiation values using using the average day of the month given by Duffie
> > and Beckman (Solar Engineering and Thermal Processes, 1991) as well as
> > running r.sun for large high-resolution rasters which I'd like to share
> with
> > the community, if I do finish them.
> >
>
> there are already other addons using r.sun, maybe you can take some
> inspiration [1]
>
> >
> > Thank you.
> >
> >
> > Regards,
> > Ben Hur
> >
> >
>
> [0] http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php
> [1] https://grass.osgeo.org/grass70/manuals/addons/r.sun.daily.html
>
> --
> ciao
> Luca
>
> www.lucadelu.org
>



-- 

*Engr. Ben Hur S. Pintor*
*Research Associate*
Phil-LiDAR 2 Project 5: REMap
UP Training Center for Applied Geodesy and Photogrammetry

*Juris Doctor*
College of Law
*University of the Philippines Diliman*
Quezon City 1101, PHL
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