google maps--handling the case when you have missed a turn

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http://stackoverflow.com – I am working on an android navigation application for blind people. So naturally no use of displaying map on the screen. My code for now gets the path by building an url and then parsing the html document. I want to make this live i.e. i want to handle the case when he/she goes off the path or goes in the wrong direction, i want my app to alert him. Is such a thing possible using a google maps feature? If possible please give details about that feature or if no such feature exists then is it posssible to use existing feature and use it in some way to help solve the problem. (If possible post t (HowTos)