I have two vector layers: one point and one polygon and I want to calculate the minimum distance of each point from the polygons (ie the distance from the closest point of the closest polygon). Is there any available plugin in QGIS for doing this? Thanks!
Try Hub Distance in the mmqgis plugin.
Lets know how you go with it!
First convert the polygon to points:
Vector -> Geometry Tools -> Extract Nodes
Add this new layer, then calculate a distance matrix between your points layer and the new polygon-points layer you just created
Vector -> Analysis Tools -> Distance Matrix
Be sure to choose "Use only the nearest (k) target points" as 1