diff --git a/modules/util/lon_lat_grid.py b/modules/util/lon_lat_grid.py
index f14c779e8507e4de6930d28a6a1facb97f556201..73cffdf3d19b837a75767483fbded46e9df923d6 100644
--- a/modules/util/lon_lat_grid.py
+++ b/modules/util/lon_lat_grid.py
@@ -44,6 +44,8 @@ class LonLatGrid:
 
         flons = flons[keep]
         flats = flats[keep]
+        self.lon_lo, self.lon_hi = flons.min(), flons.max()
+        self.lat_lo, self.lat_hi = flats.min(), flats.max()
 
         points = np.stack([flons, flats], axis=1)
 
@@ -177,6 +179,9 @@ class LonLatGrid:
 
         return outv
 
+    def check_inside(self, lon, lat):
+        return (self.lon_lo < lon < self.lon_hi) & (self.lat_lo < lat < self.lat_hi)
+
 
 DEG_TO_RAD = np.pi/180.0;
 RAD_TO_DEG = 180.0/np.pi;