3.7 Time step definition
In this form you specify which column in the file(s) is the Date column or the Date and time column . Also the correct format for this column must be specified: use a 'd' to indicate days with one or two numbers (e.g. 2 and 21), 'dd' for days with two numbers (e.g. 02 and 21), m for months with one or two numbers (e.g. 1 and 11) and 'mm' for months using two numbers (e.g. 01 and 11).
The Time column number may be left blank (or zero) if there is no separate column for the time (or the time is in the same column as the date). When you alter the column number, the corresponding column in the example file will be coloured light green.
The 'Equidistant timesteps' checkbox and the Time step mapping inputs will determine what series the import will create.
The Timebase and divider are similar to what is used in HYMOS. The three options for interpolation define how the data will be interpreted when the time stamps in the import file are to be translated to equidistant time steps. The options:
- Step : if the time stamp in the impor data is not within one second after the time as defined in the equidistant step, the value on the previous time step before this is used.
- Linear interpolation : linear interpolation is used to compute the value on each time step.
- Window : before and after the equidistant timestep a search window is kept. If no value is available in this window, the equidistant timestep gets the value "missing". If more timestamps are found in this window, the value store is the average (arithmetic mean) of the values on these time stamps.
An example of the time step methods is shown in Table 7 and Table 8.
Table 7: Original series in import file
time stamp |
value |
14:00 |
1 |
15:10 |
2 |
16:01 |
3 |
16:59 |
4 |
18:00 |
5 |
19:01 |
6 |
20:00 |
7 |
21:00 |
8 |
Table 8: Hourly series saved to database for diferent interpolation options and import file in Table 7.
time |
step |
linear |
window 60 sec |
14:00 |
1 |
1 |
1 |
15:00 |
1 |
1.857143 |
|
16:00 |
2 |
2.980392 |
3 |
17:00 |
4 |
4.016394 |
4 |
18:00 |
5 |
5 |
5 |
19:00 |
5 |
5.983606 |
6 |
20:00 |
7 |
7 |
7 |
21:00 |
8 |
8 |
8 |
By specifying first and last date of the import, you may limit the import to a part of the file containing dates between these limits. For the last date to import you may specify the word "now". This will be evaluated during the actual import to the date and time of the PC on which the import takes place.
If you want to keep the original time stamps and the raw data it is recommended that you import the data as non-equidistant and perform further processing inside HYMOS.
Example file
In our example file the Date column is column 1, with format yyyymmdd and the Time column is in column 2 with format hhmm. The Time step is 10 minutes, so hour divided by 6.
