Time sequence (Water Overlay)
In the Water Overlay, a number of elements can be configured as a time sequence rather than a single value. This means that during the simulation, the value used for calculations changes over time.
Time sequences can be loaded in via two methods: directly as attributes of imported Geo data, or by importing a CSV file via the configuration wizard.
Structure of a time sequence
Time sequences are stored in project data in the form of attribute arrays. It consists of an array of numbers where numbers at even indices represents a time in milliseconds and numbers at uneven indices are the values related to that time. A maximum of 10.000 values (5.000 pairs) can be used for any single sequence,
Conceptually, a time sequence is always structures as follows:
| Time (seconds) | Value |
|---|---|
| 3600 | 0.03 |
| 7200 | 0 |
| 9000 | 0.03 |
| 10800 | 0.06 |
The unit for time is stored in seconds. The unit for the value is dependent on the element for which the time sequence is used. Each number representing a time in the array should be larger than the previous number.
Depending on the type of element you wish to configure using a time sequence, the interpretation of a time sequence can differ.
Definition by end
Rainfall and evapotranspiration use an interpretation by which the times indicate up to when the value is used.
Definition by start
Values obtained using this procedure remain stable until the simulation-time passes the time stored at the next index, at which moment the next value is selected. Values are therefore not interpolated. In case the first time is larger than 0, a default value of 0 is used.
The speeds of hydraulic structures are obtained using this interpretation.
Interpolated
Heights and target water levels of breaches and hydraulic structures use an interpretation by which the used value is interpolated based on the current time in the simulation, the preceding and upcoming defined time in the time sequence, and the associated value.
Structure of data
There are multiple methods to load a time sequence in the Tygron Platform, and depending on the method the data will be structured slightly different to load it in.
CSV
See the How-to's on the CSV page.
Attribute
When importing a time sequence in an attribute while importing geo data, the attribute should contain a list of values which looks as follows:
[3600, 0.03, 7200, 0, 9000, 0.03, 10800, 0.06]
The first value is the time for the first time-value pair, the second value is the value of that pair. The third value is the time for the second time-value pair, and so forth.
Notes
- When exporting data which has a time sequence for an attribute, it is formatted in the same structure which can be used to load it back in as an attribute.