If you're confident in the quality of the touch-screen, your design is a good one.
Some points to note:
Some touch panels, particularly bigger ones, have quite a lot of noise and can have "dead spots" where the touch is not (as easily) registered. You may want to delay snapping back the item once you notice the touch event finishing if you can.
It's not ...
Let's assume for a moment that we're talking about a touch interface without any other controls.
As noted in the comments above, there are a limited number of gestures for directly manipulating content. From gestureworks:
The Tap family are all out.
Rotation is possible, but unlikely to be intuitive. It's also not particularly ...
Your primary consideration should be whether the UI behaves the way the user expects. If it's intuitive, drag and drop away. You can use hallway testing to check if your UI is intuitive. In that situation, dragging and dropping appears to be the most sensible as well as the easiest course of action, so there are few (if any) reasons you shouldn't use drag ...
It's bad UX to not have drag and drop in an iPad app. Tablets are all about direct manipulation. The D&D is so native to the apps that you don't even notice it when you say that there's no D&D in iPad apps - basically most of your interaction with the device is pure D&D. For most of the actions that you'll provide, users will expect there to be a ...
This won't work with just thumb, but neither does pinch.
Have the user put 4 fingers spread on the screen, the map then zooms in so that the polygon whose vertices are your fingers fills the whole screen. To me this seems much more intuitive than pinch zoom, especially for pictures and maps. For instance, if I have a picture with a face in it, I just put ...
One thing to keep in mind is that touch-move-finger is also used to scroll and page swipe. So if you don't need scrolling you can use touch-move-finger for dragging objects. But you can't have both (comfortably).
Mobile apps are essentially all tough/drag and drop interface. The concern with your layout is whether it will be too much work for users to drag and sort all those items compare to tap highlight and bulk move with a button.
Judging from the screenshot you provided, it's probably more ideal to not ask the users to d&d sort that many items as appeared.
The thing with Touch is despite all the talk of "gestures" there are really only a few basic gestures humanly possible:
Tap and hold
Drag (swipe with constant physical contact)
As you'll note even these gestures you're partially repeating yourself; tap and hold is just a longer tap, swiping is just dragging but letting go quickly.
Firstly with Google Maps there are two routes to a location
If an location information is always displayed same place regardless of the route used to find it this is a UX win in terms of Consistency heuristic.
Secondly note that in Google maps the linear menu changes. This means that a radial menu would alter. And thus any benefit ...
If you're changing the order of items that means the options are going to keep jumping around the place whenever you make a change. This is just confusing.
OK, in your example it's pretty obvious that '2' will come after '1' and before '3', but you won't be using numbers here - you'll have options like 'Email', 'SMS', 'Phone' etc. Users won't know that the '...
I think icons are fine to a degree, however when you need to display information that isn't easily represented by icons, I'd revert to text.
In use (sorry I don't have the same icons, hopefully you get the picture)