[mkgmap-dev] DEM: performance with bicubic interpolation

Wed Jan 24 13:09:18 GMT 2018

Hi Andrzej,

yes, your original patch dem-align-6.patch implements bicubic-catmull and the faster replacement by Paul Breeuwsma does that as well.

Gerd

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Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej at poczta.onet.pl>
Gesendet: Mittwoch, 24. Januar 2018 13:45
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] DEM: performance with bicubic interpolation

Hi,

I have added more algorithms for testing, patch is attached. Patched
mkgmap recognize following values for x-dem-interpolation:
bilinear
bicubic
bicubic-spline
bicubic-catmull
bicubic-hermite

I have prepared new set for testing:
http://files.mkgmap.org.uk/download/408/interpolation2.7z

For me bicubic-catmull looks like bicubic. Bicubic-spline looks inferior
and bicubic-hermite gives weird results, maybe something is wrong.

Still bicubic interpolation looks the best.

--
Best regards,
Andrzej