For a data set with uniform cadence with no averaging selected, this is the same as no filtering. Maximum/Minimum - For a data set that has been averaged to a uniform cadence, this is the maximum/minimum value in the averaging interval.For a data set with uniform cadence with no averaging selected, this is either 1 or 0. Number Valid - For a data set that has been averaged to a uniform cadence, this is the number of values used in the average.The filtering option is used primarily by Autoplot in order to allow large time ranges to be visualized by loading only the data required to give the same pixel view as if all of the data were loaded. The first value in a given file with one day of data may have an averaging interval that starts 30 seconds into the previous day. One example is some 1-minute ground magnetometer data files. Note that there are exceptions to the convention of a time stamp labeling the start of the averaging interval in a text file with data on a uniform time grid. Then the corresponding output file will contain If this is the case, then the data served by ViRBO will be on a uniform time grid, but there will be a one-to-one match between the original data and the served data only where there are non-fill data.įor consistency, timestamps are placed at the center of the interval when the timestamps in the original file labels the start of the interval but the averaging interval is the entire interval. Some data are manipulated more quickly if they are on a uniform time grid (this depends on how much the data compresses and the sparseness of the data). NaN is used to represent either a fill value when the data was placed on a uniform time grid or a invalid data point that was, for example, indicated by -999 in the original data file. If all values are NaN, the average is NaN.ĭata served by ViRBO all have a uniform fill value of IEEE 754 NaN values. For example, if the native cadence is 6 hours with timestamp/value pairs of

For example, if the cadence is six hours and the start date is July 4, 2000, then the output would beĪ MATLAB script is returned that loads the selected data into memory.Īn IDL script is returned that loads the selected data into memory.Īveraging is performed by computing the block mean of the valid data points. The numbering is relative to the start day. If any of MM, SS, MS (millisecond), ms (microsecond), or ns (nanosecond) is always zero, it is omitted.

Read cdf files in matlab