diff -r f440529b9606 -r cfb0607e5afc gpx_plot.py
--- a/gpx_plot.py	Sat May 23 16:51:16 2020 +0200
+++ b/gpx_plot.py	Thu Jun 15 08:46:26 2023 +0200
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf8 -*-
 
 '''
@@ -46,7 +46,7 @@
 # find gnuplot binary
 gnuPlotCmd = which (options.gnuplot)
 if not gnuPlotCmd:
-    print '***', options.gnuplot, 'does not exist or is not executable\n'
+    print ('***', options.gnuplot, 'does not exist or is not executable\n')
     parser.print_help ()
     sys.exit ()
 
@@ -109,9 +109,9 @@
     
     # import xml data from files
     if not os.path.exists (fname):
-        print fname, 'does not exist'
+        print (fname, 'does not exist')
         continue
-    print 'opening file', fname
+    print ('opening file', fname)
     infile = open (fname)
     tree = etree.parse(infile)
     infile.close()
@@ -134,7 +134,7 @@
             times = [datetime.datetime.strptime(trkpt.find(nsmap + 'time'
                                        ).text, timeformat) for trkpt in trkpts]
         except Exception as e:
-            print '-- trackpoint without time'
+            print ('-- trackpoint without time')
             times = None
 
         # save original trackseg for plotting
@@ -147,12 +147,12 @@
             sumy += y
             sumz += z
 
-        print 'segment %d, with %d points:' % (si, n)
+        print ('segment %d, with %d points:' % (si, n))
         ntot += n
 
     tracks.append (tracksegs)
     npoints.append ((fname.replace ('_','\_'), ntot))   # underscore -> subscripts in gnuplot
-    print 'number of points in track %s = %d:' % (fname, ntot)
+    print ('number of points in track %s = %d:' % (fname, ntot))
 
 latm, lonm, elesum = xyz_to_latlonele (sumx, sumy, sumz)
 
@@ -179,9 +179,9 @@
 
 from subprocess import Popen, PIPE
 try:
-    plot = Popen ([gnuPlotCmd], stdin=PIPE, stdout=PIPE, stderr=PIPE)
+    plot = Popen ([gnuPlotCmd], stdin=PIPE, stdout=PIPE, stderr=PIPE, text=True)
 except Exception as e:
-    print e, 'while executing', gnuPlotCmd
+    print (e, 'while executing', gnuPlotCmd)
     sys.exit ()
 
 range = 'set xrange [%f:%f]\nset yrange [%f:%f]\n' % (xmin, xmax, ymin, ymax)
@@ -193,4 +193,4 @@
 plot.stdin.write ("\n".join (data))
 plot.stdin.write ('\n')
 plot.stdin.flush ()
-raw_input ('press enter to exit program')
+input ('press enter to exit program')