Hi Gerd, Ok, we should first investigate if there really is a limit for a tile size. Just for now it may be good if splitter issues a warning for tiles that exceeds a limit, e.g. "Tile xxxxx.osm.pbf covers more than n° in latitude. This may cause problems with mkgmap when using one of the options bounds, generate-sea and precomp-sea. <some hints what can be done to avoid that>". I think my testcase is not ideal. I have used a polygon that covered the whole tile. But this causes large (too large) img sizes because the polygon has to be split into many subpolygons when mkgmap splits into subdivisions. I think instead it is better to use one POI node in each corner of the bbox. I will try again and report about my findings. WanMil
Hi WanMil,
I think the maximum values should be as large as possible. When splitting planet, we have a huge tile covering an area in the pacific, this tile has almost no nodes. If splitter has to create tiles with max. 20 degrees width we probably see tiles without nodes.
Gerd
Date: Fri, 30 Nov 2012 18:18:02 +0100 From: wmgcnfg@web.de To: mkgmap-dev@lists.mkgmap.org.uk Subject: Re: [mkgmap-dev] splitter maximum tile size
Thorsten Kukuk wrote
No, there is no limit for the maximum tiles size for now. Thanks for the hint. What is the limit? I guess it is not a constant, but depends on resolution and other values? Unfortunately the test data is gone and I didn't download it.
If you want to look at the problem, I can try to regenerate the data again.
I am not sure if the problem has to be solved in splitter or in mkgmap. Anyway, please try to reproduce it. I also like to know why mkgmap has problems with tiles that contain only very few nodes. Or is it the gps device that has problems?
Gerd
I played a little bit with a small testfile how large a tile can be. The attached test file has the maximum size which works for me: <bounds minlat="0.0" minlon="0.0" maxlat="85.0" maxlon="179.98"/> Larger bounds cannot be put into a single tile.
For large tiles mkgmap requires much memory problem if the bounds parameter is set. They need to be completely loaded with a high memory consumption.
I don't know if there is a hard limit for the tile bounds size. Maybe using some limits in splitter for the maximum latitude and maximum longitude size would remove some problems, e.g. max lat = 20, max long = 20.
WanMil
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