diff --git a/modules/util/viirs_l1b_l2.py b/modules/util/viirs_l1b_l2.py
index e802b361a9da835a7875c8820291ae76523bda7c..faf2004be906373559a5c390995f4f3391ec107f 100644
--- a/modules/util/viirs_l1b_l2.py
+++ b/modules/util/viirs_l1b_l2.py
@@ -106,7 +106,7 @@ def run(l1b_h5f, l2_h5f, l1b_tiles, l2_tiles, factor=2):
 
     num_keep_x_tiles = 5
     i_skip = int(mod_num_x_tiles / num_keep_x_tiles) * mod_tile_width
-    i_start = int(mod_num_pixels / 2) + int((num_keep_x_tiles * 3 * 64) / 2)
+    i_start = int(mod_num_pixels / 2) - int((num_keep_x_tiles * 3 * 64) / 2)
 
     num_keep_y_tiles = 16
     j_skip = int(mod_num_y_tiles / num_keep_y_tiles) * mod_tile_width