<html><body>Hallo Hanlie
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To be honest, I have no idea how the extension in ARCGIS works. It is part of the spatial analysis package. I will read up on the r.sun thanks.
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I think I've found the problem with the aspect. When I created the DEM, I just imported the vector line data. Someone told me that when they make the DEM in ARCGIS, they use line and point data. I have both, how to I use both to create the DEM in with GRASS?
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Thanks for the reply :)
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<br />
JACO ENGELBRECHT
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Viticulturist
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C: +27 82 801 3299
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E: jaco@bolandkelder.co.za
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T: +27 21 862 6190
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F: +27 86 521 6147
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W: www.bolandcellar.co.za
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<br />
<br />
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<br>-----Original Message-----
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From: africa-bounces@lists.osgeo.org [mailto:africa-bounces@lists.osgeo.org] On Behalf Of Hanlie Pretorius
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Sent: 11 March 2015 07:55 AM
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To: africa@lists.osgeo.org
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Subject: Re: [OSGeo Africa] Potential Solar Radiation
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<br />
Hi Jaco,
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I didn't reply yesterday because I was hoping that someone with more knowledge than I have, would.
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I need some clarification before I can possibly help you.
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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.
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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.
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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?
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Regards
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Hanlie
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<br />
> From: africa-bounces@lists.osgeo.org
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> [mailto:africa-bounces@lists.osgeo.org]
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> On Behalf Of Jaco Engelbrecht
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> Sent: 09 March 2015 04:47 PM
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> To: africa@lists.osgeo.org
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> Subject: [OSGeo Africa] Potential Solar Radiation
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>
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> Hello, me again.
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>
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> I have two questions today:
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>
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>
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> 1. Is there an easy (and understandable - I'm not a programmer nor a
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> GIS expert) way to make Potential Solar Radiation (I think you also
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> call it irradiance maps) in QGIS? I know in ARCGIS it isn't too
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> difficult, but I don't have ARCGIS and really need to make these maps.
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> Find example attached (Original data was made in ARCGIS)
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>
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> 2. I made my own 5m DEM with 5m Contours. How do I smooth out my end
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> product of Aspect and Slope (already using Bilinear resampling)? And
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> why is there no data to show (as you can see in the middle of the
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> map)? How can I get it to fill in that gap, like the one in ARCGIS?
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> (Find example attached)
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>
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> Any help would be greatly appreciated.
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>
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> Best regards,
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>
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>
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> JACO ENGELBRECHT
<br />
> Viticulturist
<br />
>
<br />
> C: +27 82 801 3299
<br />
> E: jaco@bolandkelder.co.za<mailto:jaco@bolandkelder.co.za>
<br />
> T: +27 21 862 6190
<br />
> F: +27 86 521 6147
<br />
> W: www.bolandcellar.co.za<http://www.bolandcellar.co.za/>
<br />
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