GPSVisualizer allows creation of text files with coordinates for any polygon (or line etc). Then use R's read.delim to create dataframes. Assume two dataframes are named poly1, poly2, poly3.
Convert a single set of coordinates into a polygon. Note the area is already calculated!
OnePoly=Polygon(poly1) TwoPoly=Polygon(poly2) ThreePoly=Polygon(poly3) OnePoly@area OnePoly@bbox
Groups of polygons can be combined into Polygons, and subsequently into SpatialPolygons. This matches the structure of Spatial Classes: groups of polygons. This can now be plotted etc. There is also a way to add your down data slot, ie a dataframe with information about each of the Polygons. You need to create a dataframe with one row per group of polygons. Assume below it is named YOURDATA.
Polys12=Polygons(list(OnePoly,TwoPoly)) Polys3=Polygons(list(ThreePoly)) SPoly=SpatialPolygon(list(Polys12,Polys3)) sp::plot(Spoly) ## map omitted slotNames(Spoly) # SPolyData=SpatialPolygonsDataFrame(SPoly,<i>YOURDATA</i>)