[Gnuplot-py-users] Problem using gnuplot.py from cron on cygwin under W2K

Hello and thanks for the efforts on gnuplot.py, really a nice tool.  I'm 
hoping you might have some insight into a problem I'm having as a 
relatively new python and gnuplot.py user.

I've written a rather brute force script that generates png plots  of 
various meteorological fields for posting on a web page.  When I run it 
from the command line it functions beautifully and generates all my 
plots in the locations I want them.  If you are curious to see the 
results what I'm doing you can look at:

http://neige.bren.ucsb.edu/mmsa/images/weekly/default.htm
&
http://neige.bren.ucsb.edu/mmsa/images/daily/default.htm

When I go to run the routine scheduled from a cron entry however, it 
chokes.  The system I'm on is running W2K server and I've got cron 
running under cygwin which calls various scripts every hour to generate 
the pages I need.  Other python scripts work fine in this manner, for 
example, the following page:

http://neige.bren.ucsb.edu/mmsa/images/hourly/LatestMet.htm

is automatically generated hourly from a seperate python script called 
from the same cron entry.

So, the code (Plotmmsa.py) I'm having trouble with is:

_________________________________________________________
#...bunch of prep stuff cut out for brevity...
print "Read in and set various lists, starting plots. Last depth reading:"
print PlatformTemp[-1:] #make sure we've got data in our lists (we do).

#g = Gnuplot.Gnuplot()
g = Gnuplot.Gnuplot(debug=1) #debug=1 outputs gnuplot commands to stdout
g('set data style lines')
#g('set data style linespoints')
g('set term png color')


g.title('Temperature')
g.xlabel('Day of Year')
g.ylabel('Degrees C')
#This is line 106 which seems to be the problem:
g('set output "/home/mmsa/wwwroot/mmsa/images/weekly/PlatformTemp.png"')
g.plot(PlatformTemp[-700:]) #Plot the last 7 days of data.
time.sleep(1)		#Wait for gnuplot to do it's thing.
g('set output "/home/mmsa/wwwroot/mmsa/images/daily/PlatformTemp.png"')
g.plot(PlatformTemp[-96:])  #Plot the last day of data.
time.sleep(1)		#Wait for gnuplot to do it's thing.
#...Rest of plots left out for brevity...
__________________________________________________________


Output from running Plotmmsa.py at the command prompt:

$ ../bin/python/Plotmmsa.py
Read in and set various lists, starting plots. Last depth reading:
[[7.458333333333333, 3.8610000000000002]]
gnuplot> set data style lines
gnuplot> set term png color
gnuplot> set title "Temperature"
gnuplot> set xlabel "Day of Year"
gnuplot> set ylabel "Degrees C"
gnuplot> set output "/home/mmsa/wwwroot/mmsa/images/weekly/PlatformTemp.png"
gnuplot> plot '/cygdrive/c/WINNT/TEMP/@1648.0' notitle
gnuplot> set output "/home/mmsa/wwwroot/mmsa/images/daily/PlatformTemp.png"
gnuplot> plot '/cygdrive/c/WINNT/TEMP/@1648.1' notitle
__________________________________________________________

Output from cron running the same program:

gnuplot> set data style lines
gnuplot> set term png color
gnuplot> set title "Temperature"
gnuplot> set xlabel "Day of Year"
gnuplot> set ylabel "Degrees C"
gnuplot> set output "/home/mmsa/wwwroot/mmsa/images/weekly/PlatformTemp.png"
gnuplot> plot '/cygdrive/c/WINNT/TEMP/@1984.0' notitle
gnuplot: not found
Read in and set various lists, starting plots. Last depth reading:
[[7.458333333333333, 3.8610000000000002]]
Traceback (most recent call last):
   File "/home/mmsa/bin/python/Plotmmsa.py", line 106, in ?
     g('set output "/home/mmsa/wwwroot/mmsa/images/daily/PlatformTemp.png"')
   File "/usr/lib/python2.2/site-packages/Gnuplot/_Gnuplot.py", line 
206, in __call__
     self.gnuplot(s)
   File "/usr/lib/python2.2/site-packages/Gnuplot/gp_unix.py", line 203, 
in __call__
     self.flush()
IOError: [Errno 32] Broken pipe

_________________________________________________________

Any suggestions would be much appreciated.  My next step will be to get 
gnuplot.py running on a linux box and see if I have the same problems there.

Thanks in advance,
mtc

-- 
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Michael Colee                        Internet: mt...@ic...
ICESS & Bren SESM                    Phone   : (805) 893-2883
University of California             Fax     : (805) 893-6113
Santa Barbara CA 93106-3060          Office  : 1001 Bren Hall
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