[mkgmap-dev] Splitter Error

Tue Mar 12 10:24:26 GMT 2013

RheinSkipper wrote
> I want to establish the order I need via a preprocessing. This
> preprocessor (programmed by Malcolm) is already working perfectly. 
> 
> All I need from mkgmap is not to mix up this order. 

OK, that is understood. With --preserve-element-order and mkgmap >= r2507
the order is not mixed in the program, means, two executions of the program
with the same input should give the same output (besides some time stamp
values in the img file).
The problem remains: The garmin img format is not flat, it requires us to
build 
sub divisions with a lot of restrictions regarding the size and number of
elements in it.
Thus, two polygons maybe be placed in the same sub division or not. 

I see only one possible solution: We could change the algo that creates sub
divisions completely so 
that we first calculate the subdiv rectangle, next place all objects into
it. If that rectangle doesn't fullfil the restrictions, divide it into two
or more rectangles and place all objects into the parts by cutting anything
that is not completely within the smaller rectangle. 
The current algo doesn't cut anything, so this change will probably require
a lot more
time and spcecial routines to care about routing and rounding errors caused
by the cutting.

I don't know if that was already tried before?

Gerd

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