There are some design issues that I think you'd be interested in, with doing GPS navigation on a dragged route as opposed to presenting a static set of steps on it. The thing is that in GPS navigation, when I drive off route, you recalculate to get me back to where I'm going. For a "from A to B" route, you recalculate "from current location to B", simple. For a "from A via V to B" route, do you calculate "from current location via V to B"? Well, then if I set V on Bridge 1 but go over Bridge 2, my GPS is going to keep insisting I go back and hit Bridge 1, even if it's pointless now. We can suggest some heuristics to try, like don't go back to V is that's more than K% slower than skipping it, but there is a lot of potential for giving the user the impression we're being flaky and unpredictable.
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Date: 2018-04-18 07:09 am (UTC)There are some design issues that I think you'd be interested in, with doing GPS navigation on a dragged route as opposed to presenting a static set of steps on it. The thing is that in GPS navigation, when I drive off route, you recalculate to get me back to where I'm going. For a "from A to B" route, you recalculate "from current location to B", simple. For a "from A via V to B" route, do you calculate "from current location via V to B"? Well, then if I set V on Bridge 1 but go over Bridge 2, my GPS is going to keep insisting I go back and hit Bridge 1, even if it's pointless now. We can suggest some heuristics to try, like don't go back to V is that's more than K% slower than skipping it, but there is a lot of potential for giving the user the impression we're being flaky and unpredictable.