gensky result different from that in, Axel's tutorial

Thank you very much indeed, Axel and Greg!


On Thu, Jun 24, 2010 at 12:36 AM, Greg Ward <[email protected]> wrote:

Just a side-note: the turbidity factor is _only_ used by gensky to
estimate the zenith luminance. If the horizontal irradiance or zenith
radiance is given using -B or -b (respectively), turbidity is ignored.


From: Axel Jacobs <[email protected]>

Date: June 23, 2010 8:27:12 AM PDT

Hi Ji Zhang

> So, Which output is the correct one? What might causes the
> differences?

The Radiance Tutorial must be about ten years old now. I keep updating it,
fixing small typos and inconsistencies, but have not felt the need to
reflect the recent changes to gensky's turbidity.

Both, CIE clear and overcast are extremes that are fairly unlikely to
occur in reality. As Greg said, you really need to feed in measurements, and
also have a good guess at the turbidity if you are concerned about accuracy.
If you can supply diffuse and direct irradiation, you might want to use
gendaylit instead.


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ZHANG Ji 张冀 (PhD) :: Research Fellow :: Centre for Sustainable Asian Cities
:: School of Design and Environment :: National University of Singapore :: 4
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