[GRASS-user] Difference in sunset/sunrise time between r.sun and r.sunmask

[Büro Seling]

Am 02.01.2012 16:19, schrieb Stephen Sefick:
> If you use R there is a sunrise.set function in the StreamMetabolism 
> package (shameless promotion).  That may be helpful.
>
> Stephen Sefick
>
> On 01/02/2012 06:57 AM, Büro Seling wrote:
>> Dear Group!
>>
>> Happy New Year @all!
>>
>> I work on a Linux GRASS 6.4.2 RC1. The area of interest is in central 
>> Europe and
>> the projection is WGS84(EPSG:4326).
>>
>>
>> When I use the r.sun module and let it show the sunset/sunrise time 
>> and compare
>> it with the sunset/sunrise from a map created with r.sunmask I see great
>> differences (up to 50 minutes).
>>
>>
>> It is not the timezone (which is set correctly) in r.sunmask.
>>
>> The results from r.sunmask seem to be, according to other sources, 
>> seem to be
>> right, but the results from r.sun are fare off.
>>
>> Please give a suggestions or help!
>>
>> Stefan
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>
Thanks for Your suggestion Stephen,
but I have to make "shadow" maps with r.sun and my problem is how to get 
r.sun work within the correct sunrise/sunset timespan.