Thursday, June 6, 2013

Errors with the sampling rate

The plots shown in the previous post seemed to have some discrepancies; some of the subplots were not synchronized in time with the rest. Looking at the sampling rates and the number of data points for the SAC files revealed an issue. Two of the stations had reported a sampling rate of 62.4999961853 Hz instead of 50 Hz. Another 6 stations reported 3002 data points instead of 3001 like the rest.

One way to resolve the first issue was to simply ignore those stations, another was to downsample the data to 50 Hz.

For the stations reporting 3002 data points, the issue seemed trivial and it looked like it would not make a difference to the plot. But that does not seem like the case now that I have tried to plot it. The plot is shown below; clearly there is still an error.



Removing these 8 stations from the data set however resolves the issue. There should be a more elegant solution than simply eliminating data points, however for now, it works!

It also took a lot of time to figure out how to get rid of the axis labels and ticks for 183 subplots, while still having one for the entire plot. It does look cleaner now-






No comments:

Post a Comment