[MSNoise] plotting error

[Kasper van Wijk]

Dear All,

The whole cron.sh was humming a long nicely on our MSNoise network, until I
changed from stacking 1,2 and 5 days (initially) to 1,2,3,4,5,30 days. Now,
all steps seem to run UNTIL the plot command. Here is the error (after
putting a print statement on the cause of the problem, df):

(I run as sudo, because root is running the cron.sh overnight:)

[kasper at localhost MSNoise-master]$ sudo python s07plot_dtt.py
loading 1 days
Empty DataFrame
Columns: [A, EA, EM, EM0, M, M0, Pairs]
Index: []
Empty DataFrame
Columns: [A, EA, EM, EM0, M, M0, Pairs]
Index: []
Traceback (most recent call last):
  File "s07plot_dtt.py", line 102, in <module>
    alldf = alldf.append(df)
  File "/usr/lib64/python2.7/site-packages/pandas/core/frame.py", line
4266, in append
    verify_integrity=verify_integrity)
  File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line
883, in concat
    return op.get_result()
  File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line
964, in get_result
    new_data = self._get_concatenated_data()
  File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line
1007, in _get_concatenated_data
    new_data[item] = self._concat_single_item(rdata, item)
  File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line
1094, in _concat_single_item
    return com._concat_compat(to_concat, axis=self.axis - 1)
  File "/usr/lib64/python2.7/site-packages/pandas/core/common.py", line
1191, in _concat_compat
    axis=axis)
ValueError: need at least one array to concatenate