2019-03-13, 01:25 PM
(2019-03-11, 09:28 PM)abarrow Wrote: Okay, now that I've updated RPI firmware and I have wireless working, I've been trying OpenCPN 4.99 on my PI. One thing I've been trying is mbtiles support.
It does work, and surprisingly, the mbtiles files that I created with SASPlanet are considerably smaller than KAP files of the same areas. That's the good news. The not-as-good news is that OpenCPN is slower, and when using mbtiles seems to take the processor to 100% while scaling or moving the map.
Did you try compressing kap files with xz? OpenCPN has the option to compress charts, and the size difference shouldn't be much between these two once compressed if they are the same chart.
mbtiles uses png compression which is better than tif used by kap, however mbtiles only come at fixed zoom levels, so an arbitrary scale size kap converted to mbtiles will lose data or increase file size.
The mbtiles support in opencpn is not optimized, so it is not a surprise it is slow.
Quote:I need to go back to the KAP files and see what sort of difference it makes in terms of speed and CPU load.
One extra bonus on all this: after getting everything upgraded on an SD card, I used dd to copy the entire card to a USB-attached SSD. For the first time I'm now able to boot OpenPlotter directly from the SSD without the use of an SD card. Previously I wasn't able to get it to work, and resorted to using an SD card with only a /boot partition, pointed to the SSD. Using the SSD has improved speed of loading and of the boot process, even with the built-in delay.
Nice!