applet demos


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See also applet_guide, Video [1], and #Spectrogram

1. Time Series Browse

Example use of time series browse server. The server is set up to allow the user to interactively browse long time ranges of very high resolution data. The bottom panel shows a 1-second time series over 11 years. To zoom, use your mouse to draw a box around some data.

As you zoom in on the bottom panel, you will be able to see the mechanism that allows this ~ 365x86400x11 point (~ 2.5 GB if numbers are represented as 8-byte floats) time series to be viewed interactively. The plotting program recognizes that there are only a certain number of pixels available to render the plot on the user's screen. Instead of requesting all of the data points and then rendering them, the plotting program simulates what would be rendered on the screen by requesting fewer data points from the server. The server is set up to allow fast responses to the required data operations (min, max, and average in a time window) needed to support this type of data request.

Top panel: Daily averages of 1-second data.

Bottom panel: Unaveraged data.

Use the box-zoom feature of Autoplot to figure out why the daily-averaged data in the top panel has spikes whereas the full resolution does not show spikes. Answer below.



2. Answer

Spikes appear in the daily-averaged data on days when there were very few data valid data points and the valid data points are mostly positive or negative.

3. Spectrogram


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