diff --git a/topologytool.py b/topologytool.py
index cf61abe..bf68b10 100644
--- a/topologytool.py
+++ b/topologytool.py
@@ -31,6 +31,8 @@ class Topology:
         self.iso_country = iso_country
         self.subregion = subregion
         self.linemap_size = linemap_size
+        self.linemap_xscale = 1.0 * self.linemap_size[0] / linemap_cols
+        self.linemap_yscale = 1.0 * self.linemap_size[1] / linemap_rows
         self.linemap_rows = linemap_rows
         self.linemap_cols = linemap_cols
         self.linemap_width = linemap_width
@@ -55,6 +57,7 @@ class Topology:
             self.target_region_name=self.subregion
         self.elevation_filename = self.storage_directory + "/" + self.target_region_name+".png"
         print("Elevation file name is [{}]".format(self.elevation_filename))
+        print("requested linemap size is {}, xscale is [{}], yscale is [{}]".format(self.linemap_size, self.linemap_xscale, self.linemap_yscale))
 
 
     def list_subunits(self):
@@ -118,6 +121,7 @@ class Topology:
         frame_image.paste(elevation_data,
                           ((1224 - elevation_data.size[0]) // 2,
                    (1224 - elevation_data.size[1]) // 2))
+        frame_image.save(self.elevation_filename+".frame.png")
 
         if rotation is None:
             elevation_data = frame_image
@@ -125,21 +129,33 @@ class Topology:
             elevation_data = frame_image.rotate(rotation, expand=False)
 
         width, height = elevation_data.size
+        print(width)
+        print(height)
         grid_w, grid_h = self.linemap_rows, self.linemap_cols
 
         # Calculate cell dimensions
-        cell_w = width // grid_w
-        cell_h = height // grid_h
+        cell_w = 1.0 * width / grid_w
+        cell_h = 1.0 * height / grid_h
+        print("Cell width is w,h [{},{}]".format(cell_w, cell_h))
 
         # Calculate mean values for each cell
         # future improve -- only average non-zero values to get coastlines and edges right
+        # need to use xscale yscale to get cell window, adjust for rounding/floor error
         values = np.zeros((grid_h, grid_w))
         for r in range(grid_h):
             for c in range(grid_w):
                 # Define box (left, upper, right, lower)
-                box = (c * cell_w, r * cell_h, (c + 1) * cell_w, (r + 1) * cell_h)
+                box = (int(c * cell_w),
+                       int(r * cell_h),
+                       int((c + 1) * cell_w),
+                       int((r + 1) * cell_h)
+                       )
                 cell = elevation_data.crop(box)
-                values[r, c] = np.mean(np.array(cell))
+                this_array = np.array(cell)
+                if np.max(this_array) == 0:
+                    values[r,c] = 0
+                else:
+                    values[r, c] = np.mean(this_array[this_array != 0])
         return values
 
     def create_svg_file(self, rotation=None,file_index=None):
@@ -177,33 +193,34 @@ class Topology:
         cr = cairo.Context(surface)
 
         # Background
-        cr.set_source_rgb(1, 1, 1)
+        #cr.set_source_rgb(1, 1, 1)
+        cr.set_source_rgb(0, 0, 0)
         cr.paint()
 
         # Simple Orthographic Projection Matrix (pseudo-3D)
         # Projects (x,y,z) -> (x+z/2, y+z/2)
         # max height should be no more than 3 times the distance between rows, this could be a setting
-        def project(x, y, z, xscale=20, yscale=10, offset=(0, 0)):
-            shelf = 0 if z == 0 else z + 2
-            shelf = z
-            return (offset[0] + x * xscale, offset[1] + y * yscale + shelf)
+        def project(x, y, z):
+            return (x * self.linemap_xscale,   y * self.linemap_yscale - z)
             # return (offset[0] + x * scale + z * 2, offset[1] + y * scale + z * 2)
 
         rows, cols = values.shape
         max_val = values.max()
 
-        # Normalize data for visualization height (0-100)
-        norm_data = (values / max_val) * 100
+        # Normalize data for visualization height (0-100) -- max is no more than three row heights
+        norm_data = (values / max_val) * self.linemap_xscale * 3
 
         # Draw Lines along rows
         cr.set_source_rgb(0, 0, 0)  # Black lines
-        cr.set_line_width(1.0)
+        cr.set_line_width(2.0)
+        cr.set_line_cap(cairo.LINE_CAP_ROUND)
+        cr.set_line_join(cairo.LINE_JOIN_ROUND)
         x = 0
         y = 0
         for r in range(rows):
             for c in range(cols):
                 z = norm_data[r, c]
-                x, y = project(c, r, -z, xscale=800 / cols, yscale=800 / rows)  # -z to make higher values go "up" in 2D
+                x, y = project(c, r, z)  # -z to make higher values go "up" in 2D
                 if c == 0:
                     cr.move_to(x, y + 50)
                     cr.line_to(x, y)
@@ -211,27 +228,29 @@ class Topology:
                     cr.line_to(x, y)
             cr.line_to(x, y + 50)
             cr.close_path()
-            cr.set_source_rgb(1, 1, 1)
-            cr.fill_preserve()
             cr.set_source_rgb(0, 0, 0)
-            cr.set_line_width(1.0)
+            cr.fill_preserve()
+            cr.set_source_rgb(1, 1, 1)
+            cr.set_line_width(2.0)
             cr.stroke()
-        surface.write_to_png(svg_filename.replace(".svg", ".png"))
+        surface.write_to_png(svg_filename.replace(".svg", ".topo.png"))
         surface.finish()
 
 def main():
-    topology = Topology(country="Spain",
+    topology = Topology(country="Switzerland",
                         storage_directory="/Users/he/PycharmProjects/toposhirt/outputfiles",
                         subregion_mode=False,
-                        linemap_cols=170,
-                        linemap_rows=270)
+                        linemap_cols=150,
+                        linemap_rows=150,
+                        linemap_size=(1224,1224))
     topology.list_subunits()
     print(topology.get_boundingbox())
+    topology.create_svg_file()
+    sys.exit(0)
     for r in range(4*360):
         print("Rotating by [{}] degrees".format(r/4.0))
         topology.create_svg_file(rotation=(r / 4.0), file_index=r)
 
-    sys.exit(0)
 
     t2=Topology(country="United Kingdom",
                 subregion_mode=True,