Find out points outside the polygon

Question

I have a shapefile with geometries of different regions. Also I have a list of coordinate points(field_lonlat), I want to consider only those points of the list which are outside the polygon geometries using python. Below is my code to check it but trying to find a simpler version of it.

from osgeo import ogr
from shapely.geometry import Point
from shapely.prepared import prep
from shapely.wkb import loads
import json
g = ogr.Open("Polygons.shp")
points = []
for layer in g.GetLayer(0):
    field = loads(layer.GetGeometryRef().ExportToWkb())
    fieldP = prep(field)
    for x,y in field_lonlat: //field_lonlat is my list of points 
        item = Point(x, y)
        if fieldP.contains(item):
            pass
        else:
            points.append((x,y))

But my points list checks for a single polygon once and hence considers only those points which are not in it but which might be inside an another polygon.

Answer 1

I think this would make slightly more sense :

from osgeo import ogr
from shapely.geometry import Point
from shapely.prepared import prep
from shapely.wkb import loads
import json

g = ogr.Open("Polygons.shp")
list_to_remove = []
points = field_lonlat[:] # make a copy of the list
for x,y in field_lonlat: 
    item = Point(x,y)
    for layer in g.GetLayer(0):
        field = loads(layer.GetGeometryRef().ExportToWkb())
        fieldP = prep(field)
        if fieldP.contains(item):
            # remove points that are in one of the polygons
            points.remove((x,y))
            # break to avoid checking every polygon if you're already inside of one
            break