Use a multi-touch gesture to precisely position points

[dasjo]

this is just an idea and i hope, this is the right place to put it. when using an editor like iD with touch-device like your smartphone, you have the problem of the area of focus to be hidden by your finger. its obvious that placing points on the map by finger can't really be accurate.

what i'm envisioning is a way of precisely positioning points by using a multi-touch gesture: while dragging a point with one finger, pressing a second on the screen will essentially create a recangle and place the point in the center, for example visualized using two diagonals connecting the edges of the rectangle. think of your thumbs being either A+C or B+D of the following diagram and the point to be placed at E.
http://image.tutorvista.com/cms/images/38/rectangle-diagram.jpg

congratulations on your great project, regards dasjo

[DerKarlos]

At the first moment, I liked your idea because we really need a solution.
A variation would be: The thumps at A+C and the point set at B.

This way it is almost as if you use a tool, a carbon pointer. But that could also be moved with one finger. (Two fingers are most commonly used for shift and zoom at touch devices) In the code you have to have an X/Y-offset between the thump spot and the edited point. But I didn't have good reactions by users when I implemented it.

One problem is how would you start the action? Two fingers touched at the same time? Not easy if you want to select a node. Or one finger rawly at the intended spot/node and joining the second finger? I see it more to do the fine tuning at the end of a move.

May be I will make some tests with my http://TosmE.openstreetmap.de

[dasjo]

i think the most intuitive way to start the action is while dragging a point with one finger, pressing a second one.

i guess those two different solutions are easy to try once a prototype is written
a) position the point at E between the two fingers (A+C) as stated initially
b) on a crossing B of two lines from the fingers (A+C) as by your alternative

[bhousel]

Closing as stale...
We have a lot of similar issues for touch devices, and I know it needs improvement.
#1981, #2700, etc