Pressure anomaly in Select-A-Graph

[sjukmidlands]

This morning I used Select-A-Graph to view pressure over the past moth or two, as we have unusually high pressure today. I noticed a huge downward spike in the pressure, and 'zooming in' on the graph, have a reading of 0 for the pressure at 07:20 on 14th January. See attached screen grab.

However, expecting a data reading error, I went to the Jan10log.txt file to manually edit the anomaly. The entry for 07:20 corresponds with the data either side of it; there is no anomolous entry at all:

14/01/10,07:00,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.4,1322.4,19.0,42,0.0,0.9,0.9
14/01/10,07:10,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.6,1322.4,19.2,42,0.0,0.9,0.9
14/01/10,07:20,0.9,94,0.1,0,0,0.0,0,0.0,0.0,998.5,1322.4,19.2,42,0.0,0.9,0.9
14/01/10,07:30,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.6,1322.4,19.3,42,0.0,0.9,0.9
14/01/10,07:40,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.7,1322.4,19.4,42,0.0,0.9,0.9
14/01/10,07:50,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.8,1322.4,19.5,42,0.0,0.9,0.9
14/01/10,08:00,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.9,1322.4,19.6,42,0.0,0.9,0.9

Further, looking at the all time records, the lowest pressure recorded is within normal bounds...

I'm at a loss to understand how the graph could (repeatedly) show this spike yet the data doesn't seem to be there to suggest it.

Can anyone explain how this happened, and more importantly, where/how to correct it?

Thanks!
Steve

[steve]

14/01/10,07:10,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.6,1322.4,19.2,42,0.0,0.9,0.9
14/01/10,07:20,0.9,94,0.1,0,0,0.0,0,0.0,0.0,998.5,1322.4,19.2,42,0.0,0.9,0.9
14/01/10,07:30,0.9,94,0.1,0.0,0.0,0,0.0,0.0,998.6,1322.4,19.3,42,0.0,0.9,0.9

Your wind speed for that entry has a decimal comma instead of a decimal point.

[sjukmidlands]

Well spotted Steve! I'd never have noticed that as I wasn't looking at other data in the row - a lesson learned!

Thank you very much, the graphs all look fine now!

Steve