Time Series Scalar VPS Cast Data Product
Device-level scalar data products for each cast of the VPS are described here.
Revision History
- 20120530: Initial Release
Formats
This data is available as PNG plots and MAT file data.
Description
VPS Cast data products produce one file or plot for each cast of the Vertical Profiler System (VPS). A cast is defined as a single pass through the water column. Possible values include 'Up', 'Down', 'Up - In Progress', 'Down - In Progress'. The VPS may pause at various levels throughout the water column to acquire data; this behaviour does not interrupt a cast. The up and down casts are kept separate because certain instruments will perform better on either. For instance, the CTD will sample undisturbed water on a down cast as its intake is near the bottom of the of VPS. Please consult individual instruments' documentation for more information.
For each cast, a separate PNG plot or MAT data file will be produced. A generic VPS Cast plot will be a MATLAB subplot-type of plot, with a single plot for each sensor on the selected device. Each plot will have Relative Pressure (decibars) on the Y-axis and the sensor on the X-axis. Relative pressure is measured relative to 0 decibars at sea level. In this way, relative pressure approximates the water depth. To accurately measure the water depth, the water density needs to be integrated throughout the water column - such a calculation is beyond the scope of this data product. The plot will note the start and end times of the cast in the title bar. Specialized overlay plots may be available in the future for specific devices such as the CTD. The MAT-file will contain the same data as the plot. To determine the start and end times of the cast from the MAT file, access a data structure and look at the time field, i.e. data(1,1).time(1) will be the start time, data(1,1).time(end) will be the end time of the cast.
This data product is very similar to the 'Time Series Scalar Data' product, see http://wiki.neptunecanada.ca/display/DP/1
. One of the differences is that VPS Cast data is only available on a device level basis, not as individual sensors.
Discussion
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