On 29/12/2017 08:42, Jörg 'Yadgar' Bleimann wrote:
> Hi(gh)!
> 
> Am 29.12.2017 um 08:51 schrieb Thomas de Groot:
> 
>> You are welcome Yadgar. Glad to be of help. I hope you will find what 
>> you want. If there is something fundamental that I have learned since 
>> I started modelling (with POV-Ray of course!) back in the nineties, it 
>> is that for each scale you often need a different tool/procedure. It 
>> is almost impossible to use the same output for a planetary view /and/ 
>> for a landscape. Both need different approaches.
> 
> Not necessarily... at least when it comes down to heightfields. Of 
> course, for an Earth-sized planet with a circumference of about 40,000 
> kms, a decent looking heightfield without needing vertical exaggeration 
> should be at least 400,000 by 200,000 pixels, the larger the better - 
> but this full size is mostly not needed, as it is only worthwile at 
> "pedestrian views" - and then you need only a tiny fraction of the whole 
> planetary surface. Which leads me to the next question: Does POV-Ray's 
> eval_pigment() also handle 16-bit grayscale pngs correctly?
> 

I agree with Thomas. The difference in scales between domestic and 
geographical is too great for the resolution of heightfields.
But the link below might help. It is Gilles Tran's Spherical height field.

http://www.oyonale.com/modeles.php?lang=en&page=24


-- 

Regards
     Stephen

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