[mkgmap-dev] Option "preserve-element-order"

Thu Jul 2 07:53:40 BST 2009

Hi!

Thilo Hannemann schrieb:
> you say that the draw order of the polylines depends on 1. type and 2. 
> id. What do you mean by id? Is that the OSM id? Or do you refer to the 
> order the lines are written into the .IMG file?
> 
>  From what I see it certainly depends on the type of the polyline, but 
> in a way that I do not understand.

 From my observations, lines (and POIs) are drawn in the order of the 
.osm file with preserve-order on. If you use a planet file directly, it 
is already sorted by OSM id, but this is coincidential, you can change 
it to any order you like.

In my hiking map I add lines as highlighting overlays. All highlights 
have a higher type ids than regular ways. All lines are in the same map 
layer. I can control whether the highlights are drawn over or below the 
regular ways by putting them in the correct drawing order in the osm file.

If preserve-order is off, the order is randomized by mkgamp and the 
drawing order on the device is also randomized.

I have not observed a dependency on line type id. Observations are based 
on mkgmap r590 to r1001.

bye
	Nop