I am quite new to GIS using R.
What I want to do is colour the common area (inner 'circle') and the space between borders. However, if I fill the two polygons directly, the colour for the outer polygon simply overlayed the inner polygon. Is there any way to do this nicely? My codes are:
ggplot()+ geom_polygon(data = inter_Coords, aes(x = inter_Coords[,1], y = inter_Coords[,2],alpha = 0.25)) + geom_polygon(data = concave_pts, aes(x = concave_pts[,1], y = concave_pts[,2], alpha = 0.25)) + geom_polygon(data = diff_Coords, aes(x = diff_Coords[,1], y = diff_Coords[,2], fill = 'yellow', alpha = 0.25))