This example demonstrates the capability to draw a polygon and couple it to pre-drawn polygons
by "snapping" the nodes together. It is a proof-of-concept showing one possible way to draw
several polygons that share precise borders.
Click anywhere on the map to place a node and continue clicking to create new nodes. A border
will be drawn sequentially connecting the nodes. You can click on the nodes or drag them to
manipulate the border. Clicking on a line in between nodes will insert another node in between
the two surrounding nodes.
To snap the node to a point on a pre-drawn polygon, hover the mouse over one of the pre-drawn
vertices until you see a blue node appear. Upon clicking, the map will snap a new node to that
geocoordinate. The line will also snap if you drag one of the drawn nodes near one of the
pre-drawn vertices.