There is no way to calculate those without additional information.
For example, one common weight for a communications spanning tree is one divided by the bandwidth of the link, so that links with higher capacity are assigned lower "cost". Bandwidth of a link is not, however, knowable just by knowing (x,y) coordinates.
In other situations, a common weight for a spanning tree would be the distance between the nodes. Sometimes the distance is just plain euclidean distance ("as the crow flies"), but sometimes it is instead the "road distance" -- e.g., if there is a lake between the two points then the wire might have to be routed around the outside of the lake. That is not something deducible just by coordinates.
Likewise, if physical things are to be transported, the link weight would have to encode the condition of the road and the speed limits.
