Navigation System Algorithm
 

Does anyone know how the Navigation System goes about deciding which route to recommend? I'm not thinking about the choice between "Shortest Route" and "Avoid Major Highways" but rather how the program chooses routes once one of these options is selected.

Take this hypothetical example. You start on a city grid where all the blocks are square and you start from point A to go to point B. The distances would be the same whether you went north 3 blocks and then east 3 blocks or whether you went east 3 blocks and then north 3 blocks. The system makes a choice. Any thoughts on what variables come into play?

Thanks.

do a search on dykstreas (spelling??) algorhitm. It might a variation of this alghorithm I am unsure of other shortest distance algorithms