Values in the Profile Time Series table are specified by month, day, hour and minute. Each value is taken to be expressed in the same units as those specified in the Unit Type selection above.
Any data point may be added or removed from the table, except for the data points at 00:00 on 1st January and 24:00 on 31st December; these points must exist, but their values may be changed.
The Insert button adds a copy of the currently selected point immediately after it in the list, extending the list by one. The new point may then be edited. If the date or time of any point is changed, that point is moved to ensure that the list remains sorted in chronologically ascending order.
Note that there may exist multiple points for the same time. This is perfectly valid. However, in this situation, only the first and last of these points as they appear in the table will actually have a contribution to the evaluation of the profile. The first point determines the past interpolation and the last point determines the future interpolation. Consider a free-form profile with the following points defined.
The profile will interpolate between 0 and 1 for all time-steps between 00:00 on 1st January and 24:00 on 30th June. It will then interpolate between 0 and 0 for all time-steps between 24:00 on 30th June and 24:00 on 31st December. Adding a point between the two that are both on 30 June at 24h00, will have no effect on the evaluation.
Only real dates and times may be specified. 31st September, for instance, is not a real date, so a prompt will appear to enter a day value in the range 1 to 30 if such a value is attempted. Note that 29th February is only sometimes a real date – i.e. on leap years. For the purpose of free-form profiles, 29th February is considered a real date, but data specified for that date is only used by Apache when the “Treat simulation as leap year” checkbox is checked in ApLocate (see the ApLocate documentation for more details). If this is not checked and a simulation using such a free-form profile is carried out, Apache simply discards those data points and interpolates between the adjacent data points instead.
Note that values need not be only numerical – they can be formulaic too. A formula may be entered into the value field of a data point either directly or via the formula dialog, by using the “Formula” button. The rules for formulas in free-form profiles are the same as those for formulas in schedules, and are set out in more detail in section 12 Formula Profiles.
The free-form profile can be visualized over the whole year by selecting it in the list of profiles and clicking the graph icon: . The visualization of the example profile above is shown below.
. The visualization of the example profile above is shown below.