Hi Henning, this is not surprising for me. Tiles should be a bit different, if you look at them in JOSM you have to zoom to maybe 30 m. Why does the size grow? The effect of the alignment is higher precision, means, less interpolation. With interpolation, the values are averaged, so deltas are smaller and thus the number of bits to store the deltas are smaller. So, if you already used 9942 as dem-dist for level 0 before the only improvement is precision. Other users use e.g. dem-dists=3312,3312,... and for those I would also expect a decrease in size. OK? Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Henning Scholland <osm@hscholland.de> Gesendet: Donnerstag, 18. Januar 2018 15:33:56 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] splitter r585 implements new option align-for-dem Hi Gerd, I have quite bad news. My map of China increased size about 300 mb (before 1.6 Gb, now 1.9Gb) just by following this suggestion adding --align-for-dem=1200. hgt-files are same, osm-data is same. bounding polygon for splitter is same and also tiles look similar. I was using latest mkgmap (4070) for both tests and x-dem-dist=9942,9942,9942,19884,39768 x-overview-dem-dist=79536 South east asia increased from 1.15 to 1.4 Gb with same work flow. I'm sorry :-(. If you need anything or if I should test something, please let me know. Henning On 18.01.2018 01:42, Gerd Petermann wrote:
Hi all,
see http://www.mkgmap.org.uk/websvn/revision.php?repname=splitter&rev=585
If I got that right you can use dem-dist 9942 for level 0 if hgt files are in 3'' resolution and splitter was executed with --align-for-dem=1200. For hgt 1'' files use dem-dist 3342 for level 0 and --align-for-dem=3600.
This should reduce DEM size a lot AND increase precision.
Gerd _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev