Time Intervals (Spatial Temporal Prediction)
The options in this panel are based on the choice of Time Fields or Cyclic period in the step for selecting fields.
Selected Time Fields. If you select one or more time fields in the step for selecting fields, those fields are displayed in this list.
Time Interval. Select the appropriate time interval from the list. Depending on the time interval, you can also specify other settings, such as interval between observations (increment) and starting value. This time interval is used for all selected time fields.
- The procedure assumes that all cases (records) represent equally spaced intervals.
- Based on the selected time interval, the procedure can detect missing observations or multiple observations in the same time interval that need to be aggregated together. For example, if the time interval is days and the date 2014-10-27 is followed by 2014-10-29, then there is a missing observation for 2014-10-28. If the time interval is month, then multiple dates in the same month are aggregated together.
- For some time intervals, the additional setting can define breaks in the normal equally spaced intervals. For example, if the time interval is days, but only weekdays are valid, you can specify that there are five days in a week, and the week begins on Monday.
- If the selected time field is not a date format or time format field, the time interval is automatically set to Periods and cannot be changed.
If you select Cyclic period on the step for selecting fields, you must specify the fields that define the cyclic periods. A cyclic period identifies repetitive cyclical variation, such as the number of months in a year or the number of days in a week.
- You can specify up to three fields that define cyclic periods.
- The first cycle field represents the highest level of the cycle. For example, if there is cyclic variation by year, quarter, and month, the field that represents year is the first cycle field.
- The cycle length for the first and second cycle fields is the periodicity at the subsequent level. For example, if the cycle fields are year, quarter, and month, the first cycle length is 4 and the second cycle length is 3.
- The starting value for the second and third cycle fields is the first value in each of those cyclic periods.
- Cycle length and starting values must be positive integers.