[OSGeo Africa] Potential Solar Radiation

[Hanlie Pretorius]

Hi Jaco,

I didn't reply yesterday because I was hoping that someone with more
knowledge than I have, would.

I need some clarification before I can possibly help you.

1. What do you mean by 'make a radiation map'? What is the original
data source? I know of some people who have gotten irradiation data
for the whole of Africa off the Internet and then it's just a question
of displaying it.

Or is this also something that you are using your DEM for? Then I
would look at GRASS GIS's r.sun function -
http://grass.osgeo.org/grass64/manuals/r.sun.html.

2. In my limited experience with creating DEMs it looks like your DEM
has a hole at the top and that is why your slope map does as well. I
think this has to do with defining soft and hard break lines when the
DEM is generated. What procedure did you follow to create your DEM
from the 5m contours?

Regards
Hanlie

> From: africa-bounces at lists.osgeo.org [mailto:africa-bounces at lists.osgeo.org]
> On Behalf Of Jaco Engelbrecht
> Sent: 09 March 2015 04:47 PM
> To: africa at lists.osgeo.org
> Subject: [OSGeo Africa] Potential Solar Radiation
>
> Hello, me again.
>
> I have two questions today:
>
>
> 1.       Is there an easy (and understandable - I'm not a programmer nor a
> GIS expert) way to make Potential Solar Radiation (I think you also call it
> irradiance maps) in QGIS? I know in ARCGIS it isn't too difficult, but I
> don't have ARCGIS and really need to make these maps. Find example attached
> (Original data was made in ARCGIS)
>
> 2.       I made my own 5m DEM with 5m Contours. How do I smooth out my end
> product of Aspect and Slope (already using Bilinear resampling)? And why is
> there no data to show (as you can see in the middle of the map)? How can I
> get it to fill in that gap, like the one in ARCGIS? (Find example attached)
>
> Any help would be greatly appreciated.
>
> Best regards,
>
>
> JACO ENGELBRECHT
> Viticulturist
>
> C: +27 82 801 3299
> E:  jaco at bolandkelder.co.za<mailto:jaco at bolandkelder.co.za>
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