DELFT-FEWS supports checking of time series against thresholds. When thresholds are crossed, appropriate messages may be issued. Definition of thresholds is in two parts. In the first part of the configuration, the types of threshold used are defined. In the second, the values for threshold valid for a particular location and time series are defined. In this section the configuration for the definition of the thresholds is defined. DELFT-FEWS supports different types of threshold events. These include crossing of level and rate thresholds. The occurrence of a peak is also seen as a threshold event.
For each threshold defined, two additional items need to be configured. Internally DELFT-FEWS maintains threshold events as a non-equidistant time series, where the crossings are identified by an integer. For each threshold two unique integer Id's need to be assigned. One ID is used to identify the upcrossing of the threshold, the other Id' is assigned to identify the downcrossing. The exception to this is the peak threshold where only a single Id needs to be assigned to identify the occurrence of the peak event.
Similar to the Id's used for upcrossings and downcrossing, a warning level integer can be assigned to threshold crossings. This warning level is resolved to either an icon (for display in the main FEWS GUI), or a colour (for use in reports). Warning levels need not be unique. These levels are used only for level thresholds.
When available on the file system, the name of the XML file for configuring the types of thresholds is for example:
Thresholds 1.00 default.xml
Thresholds Fixed file name for the Thresholds configuration
1.00 Version number
default Flag to indicate the version is the default configuration (otherwise omitted).
levelThreshold
Root element for definition of a level threshold. Multiple entries may exist.
Attributes;
- id: Unique Id of level threshold.
- name: Name for the level threshold.
rateThreshold
Root element for definition of a rate threshold. Multiple entries may exist.
Attributes;
- id: Unique Id of rate threshold.
- name: Name for the rate threshold.
maxThreshold
Root element for definition of a peak event threshold. Multiple entries may exist.
Attributes;
- id: Unique Id of rate threshold.
- name: Name for the rate threshold.
Figure 38 Elements of the Threshold configuration
upWarningLevel
Integer level used in determining icon (through ValueAttributesMap) on up-crossing of threshold (level thresholds only).
downWarningLevel
Integer level used in determining icon (through ValueAttributesMap) on down-crossing of threshold (level thresholds only).
upIntId
Unique integer level defined in threshold crossing time series (internal) on up-crossing of threshold.
downIntId
Unique integer level defined in threshold crossing time series (internal) on down-crossing of threshold.
intId
Unique integer level defined in threshold crossing time series (internal) on occurrence of peak event.
