Can anyone shed some light on what is happening here. The maps create fine, but have missing parts. First image has missing centre of map, zoom 1-7, whole map appears at zoom 8, but with squares of polygon data missing.
Hi col,
As Jurajs mentioned, this is an issue of displaying too much data.
Keep in mind that:
- every time you zoom out 4 times the amount of data have to be rendered
- you render data on a smartphone, this means 1GHz cpu, one core, a couple of MB Ram, a usual Tileserver has at least 4cores an 32Gb ram..
To look deeper into this issue:Per default Mapsforge stores data into 3 BaseZoomlevels
- 0-7
- 8-11
- 12-22
So if you store <osm-tag key="contour_ext" value="elevation_major" zoom-appear="6" force-polygon-line="true" /> it means that this have to be prozessed (checked at least) in level 0 to 7 :shock: result is crash.
Same with <osm-tag key="contour_ext" value="elevation_medium" zoom-appear="10" force-polygon-line="true" /> it means that this have to be prozessed in level 8 to 11
I do not recommend to use elevation Data above Level 12
However, the BaseZoolLevel can be modified by the param "zoom-interval-conf".
For some Maps I use 4 BaseLevels zoom-interval-conf=5,0,6,8,7,9,11,10,12,15,13,21
0-6
7-9
10-12
13-21
With this conf. you MAY try to start contourlines (mayor, medium) at level 10,
IF you move tags that you do not realy need at level 12 to level 13.
There is another issue for rendering Data in Levels 0-11: simplification-factor"simplifies ways and polygons with a topology preserving algorithm similar to the Douglas Peucker algorithm, using as the maximum distance difference value the given simplification factor (evaluated in pixels on max zoom level of a base zoom level); on base zoom levels higher than 12, no simplification is computed, Default=5"
This means that per default ways are simplyfied in these levels to reduce memory footprint resulting in ugly/useless contourlines.
Critical Areas in Europe (not only for contourlines):Netherlands, Germany along the NL Border, UK mid+south
