[Routing] How to make the driver direction is always the north direction

[jiatao83]

Hi, Thanks for your kind reply! In fact, I have implemented the 2D transform function,and when you get a big map tile, say 600*400, you will be get an error of "Out of Memory" as you run this function.So could you please show me your algorithm, Or give me some hints? Any suggestion is welcome, Thanks. 
   However,If we rotate the map tile successfully,there is another problem, For example, If i am driving along the road toward the south, and I get an Map tile, I rotate the map tile by 180 degree, then the driving direction is north, But the road name will be reversed. I mean the road name is a part of the map tile image, it did not separate from the map tile, say the annotation. This situation is really a problem. Any suggestions about this? Thanks! Please help me!
Regards.
                                                                                                 tao

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