[mkgmap-dev] RFC: Consider heightmeters for routing

Mon Apr 6 21:21:32 BST 2009

Hello,

this is an idea which I think about some months, but have not had the 
time to do some programming. Maybe anyone else has the same thoughts, so 
I describe my idea here.

As I use my etrex mostly for biking, I think it may be usefull to 
consider th height differences of the ways ar routing.
In my area are a lot of hills and there are often ways across the hills 
and ways surrounding the hills with not much difference in length, but 
obviously a difference in height meters. It would be reasonable if the 
etrex chooses the way around the hill.

So my idea is, to virutally lengthen the roads by the height distance. 
This is, if a road has 1km and goes straight then it gets an entry of 1 
km in the routing data.. If another road has a length of 1km and a 
height difference of 10m, then it gets a length entry of 1.1km. And a 
really hilly road with a length of 1km and a height of 100m will get an 
entry of 2km.
In other words, I would add a percentage of the height to the lenght. 
This should made the etrex choose the flater roads.

1. What do you think in general of this idea?
2. Is it usefull to implement the heigth calculation for each segment 
into mkgamp or splitter or should it be an external tool?
3. Is there an existing java library, which calculates me the height of 
each coordinate from an world model (maybe based on the SRTM data)?

Any comments?

Regards,
Johann