diff --git a/mpop/satin/viirs_sdr.py b/mpop/satin/viirs_sdr.py
index 0dabdf76..a96bb09b 100644
--- a/mpop/satin/viirs_sdr.py
+++ b/mpop/satin/viirs_sdr.py
@@ -512,6 +512,7 @@ def read_lonlat(self, geofilepaths=None, geodir=None):
             geofilepaths = [os.path.join(geodir, geofilepath)
                             for geofilepath in self.geo_filenames]
 
+        geofilepaths = sorted(geofilepaths)
         logger.debug("Geo-files = " + str(geofilepaths))
         self.geolocation = ViirsGeolocationData(self.data.shape,
                                                 geofilepaths).read()