python: slope.py: Use cell size in format function.

* python/slope.py (save_xyz)[PX]: New argument.

1 files changed, 8 insertions, 4 deletions

diff --git a/python/slope.py b/python/slope.py
index da6d314..817315d 100755
--- a/python/slope.py
+++ b/python/slope.py
@@ -181,13 +181,17 @@ def plot_curve(MY, PX):
     #fig.canvas.draw()
     #fig.canvas.flush_events()
 
-def save_xyz():
+def save_xyz(PX):
+    """
+    Write channel elevation data to file.  Pixel size PX is used to
+    convert pixel indices to co-ordinate values.
+    """
     with open('1D.txt', 'w') as f:
         for xitem, yitem, zitem in zip(reversed(xch),
                                        reversed(ych),
                                        reversed(zch)):
-            f.write('{:.2f} {:.2f} {:.4f}\n'.format(0.25+xitem*0.5,
-                                                      499.75-yitem*0.5,
+            f.write('{:.2f} {:.2f} {:.4f}\n'.format(PX/2.0+xitem*PX,
+                                                      499.75-yitem*PX,
                                                       zitem))
     
 
@@ -214,6 +218,6 @@ while (True):
     elif(input_str == "p"):
         plot_curve(ytp[-1], DY)
     elif(input_str == "s"):
-        save_xyz()
+        save_xyz(DY)
     
 #print("End.")