diff --git a/opendm/cutline.py b/opendm/cutline.py
index b0d1f801..4d21694b 100644
--- a/opendm/cutline.py
+++ b/opendm/cutline.py
@@ -3,16 +3,28 @@ import shutil
 from opendm import log
 from opendm import io
 from opendm import concurrency 
-
+from opendm import get_image_size
+import math
 
 def compute_cutline(orthophoto_file, crop_area_file, destination, max_concurrency=1):
     if io.file_exists(orthophoto_file) and io.file_exists(crop_area_file):
         from opendm.grass_engine import grass
         log.ODM_DEBUG("Computing cutline")
 
+        try:
+            ortho_width,ortho_height = get_image_size.get_image_size(orthophoto_file)
+            log.ODM_DEBUG("Orthophoto dimensions are %sx%s" % (ortho_width, ortho_height))
+            number_lines = int(max(8, math.ceil(min(ortho_width, ortho_height) / 256.0)))
+        except get_image_size.UnknownImageFormat:
+            log.ODM_DEBUG("Cannot compute orthophoto dimensions, setting arbitrary number of lines.")
+            number_lines = 32
+        
+        log.ODM_DEBUG("Number of lines: %s" % number_lines)
+
         gctx = grass.create_context({'auto_cleanup' : False})
         gctx.add_param('orthophoto_file', orthophoto_file)
         gctx.add_param('crop_area_file', crop_area_file)
+        gctx.add_param('number_lines', number_lines)
         gctx.add_param('max_concurrency', max_concurrency)
         gctx.add_param('memory', int(concurrency.get_max_memory_mb(300)))
         gctx.set_location(orthophoto_file)
diff --git a/opendm/grass/compute_cutline.grass b/opendm/grass/compute_cutline.grass
index d7bdb6fd..299411c9 100644
--- a/opendm/grass/compute_cutline.grass
+++ b/opendm/grass/compute_cutline.grass
@@ -1,5 +1,6 @@
 # orthophoto_file: input GeoTIFF raster file
 # crop_area_file: input vector polygon file delimiting the safe area for processing
+# number_lines: number of cutlines on the smallest side of the orthophoto for computing the final cutline
 # max_concurrency: maximum number of parallel processes to use
 # memory: maximum MB of memory to use
 # ------
@@ -14,7 +15,7 @@ v.in.ogr input="${crop_area_file}" output=crop_area --overwrite
 g.region vector=crop_area
 
 # Generate cutlines
-i.cutlines.py --overwrite input=ortho output=cutline number_lines=16 edge_detection=zc no_edge_friction=20 lane_border_multiplier=1000000 tile_width=1024 tile_height=1024 overlap=20 processes=${max_concurrency} memory=${memory}
+i.cutlinesmod.py --overwrite input=ortho output=cutline number_lines=${number_lines} edge_detection=zc no_edge_friction=20 lane_border_multiplier=1000000 tile_width=1024 tile_height=1024 overlap=20 processes=${max_concurrency} memory=${memory}
 
 #v.out.ogr input=cutline output="cutline_raw.gpkg" format=GPKG
 
diff --git a/scripts/grass_addons/i.cutlines.py b/scripts/grass_addons/i.cutlinesmod.py
similarity index 98%
rename from scripts/grass_addons/i.cutlines.py
rename to scripts/grass_addons/i.cutlinesmod.py
index 4817a3f6..00215529 100755
--- a/scripts/grass_addons/i.cutlines.py
+++ b/scripts/grass_addons/i.cutlinesmod.py
@@ -2,8 +2,9 @@
 
 ############################################################################
 #
-# MODULE:	i.cutlines
-# AUTHOR(S):	Moritz Lennert, with help of Stefanos Georganos
+# MODULE:	i.cutlines2
+# AUTHOR(S):	Moritz Lennert, with help of Stefanos Georganos, modified by
+#               Piero Toffanin
 #
 # PURPOSE:	Create tiles the borders of which do not cut across semantically
 #               meaningful objects
@@ -301,10 +302,10 @@ def main():
 
     if nsrange > ewrange:
         hnumber_lines = number_lines
-        vnumber_lines = int(number_lines * (ewrange / nsrange))
+        vnumber_lines = int(number_lines * (nsrange / ewrange))
     else:
         vnumber_lines = number_lines
-        hnumber_lines = int(number_lines * (nsrange / ewrange))
+        hnumber_lines = int(number_lines * (ewrange / nsrange))
 
     # Create the lines in horizonal direction
     nsstep = float(region.n - region.s - region.nsres) / hnumber_lines