Question

What techniques does the community use to edit a polygon on a Bing map?

Thinking of a vector drawing program, you can select a side, add a point to bisect a side, move the point which rubberbands the bisected side, etc.

The use case is the user has drawn a polygon, but they want to adjust it or make tweaks to it once drawn.

Answer 1

As far as I know, there is no framework implementation for what you want to accomplish that would work “out of the box”. However, all the building blocks are there. You have the Polygon object to represent your polygon on the map. For the sides, you can use the Polyline. For your vertices, you can use the Pushpin. All these shapes have the ability to handle their own mouse events, so with a bit of code and a day’s work you can roll yourself a simple polygon editor.

The idea is to have a number of Polyline segments(2 vertices each) that surround your polygon. These Polyline segments would have mousedown event handlers on them so when the user clicks on a side, you know where he/she clicked. Using this information, you can now update your Polygon and the surrounding Polylines to include this new vertex.

For your vertices, you can use pushpins to visualize them. For each vertex, supply the mousedown and mousemove events. When the user clicks on on a vertex, the mousedown will fire. This is your cue that the user wants to move that vertex, so you can enable your mousemove handler for that vertex to take effect. When the user subsequently moves his mouse, you will move the vertex with the mouse, while also updating the polygon and the relevant polylines(or updated all of them if you are lazy).

Anyway here is what I have done for the project I am working on. It is a roof measurement tool but you can see that it has much of the same functionality you want to achieve, i.e. the user can edit a polygon by moving vertices. This was done using the regular v7 API so you should be able to achieve something similar as well.