I'm trying to add rain catchments to a plot. I've successfully plotted the points etc, and have done so by converting my kml to a shapefile using GISconverter and following this turorial on plotting Shapefile Polygons. However when I plot my graph I get extra lines occurring. They seem to be a 'return to origin' line. I've pointed some out with blue arrows in this image. However I'm unsure if that is the cause, I've plotted the map data in Google Maps, to check the mapping and its correct there. Please see my code below; also here for a Google Drive share folder with all the code and data sets etc (it may take a moment for the files to upload).

Any help would be greatly appreciated, I've not much experience with kml or any geography/map files. Thank you in advance.