Author: Alex Chiang
Revision Date: 2010-12-03 00:10:07 UTC

Fix metric calculations, properly taking "no data" days into account

We allow days with no stream flow into our data set. However, we must
properly handle them when calculating our metrics.

We can't add a python None data type to a floating point, so add a few
checks to ensure we won't blow up when we encounter a day without data.
Adjust the calculation for the average daily flow accordingly; a day
without data shouldn't be considered when calculating the average.

Author: Lindsay Reynolds
Revision Date: 2010-12-06 22:20:42 UTC

Account for years with only 0.00 flow days

If we encounter a year with only 0.00 flow days, we will never set
a max flow day, and we blow up when trying to print a non-existent
variable.

The fix is simple: initialize the max_flow_day and max_flow_month
to dummy values so that we can print something in this case.

Author: Alex Chiang
Revision Date: 2010-12-06 18:12:32 UTC

Account for years with only 0.00 flow days

If we encounter a year with only 0.00 flow days, we will never set
a max flow day, and we blow up when trying to print a non-existent
variable.

The fix is simple: initialize the max_flow_day and max_flow_month
to dummy values so that we can print something in this case.