FeatureAttributeValuesOverTime

The FeatureAttributeValuesOverTime is a plot operator that computes a multi-line plot for feature attribute values over time. For distinguishing features, the data requires an id column. The output is a plot in Vega-Lite specification.

xychart-beta
    title "Selected Regional Trends"
    x-axis ["Jan 05", "Feb 02", "Mar 02", "Mar 30"]
    y-axis "Value" 0 --> 250
    line "Papenburg" [118, 201, 198, 225]
    line "Wismar" [185, 158, 177, 213]
    line "Frederikshavn" [46, 50, 103, 124]
    line "Helsingor" [44, 110, 112, 128]

For instance, you want to plot the NDVI values of a feature collection of trees. Then, you can use a multi-line plot to visualize the trees by their id.

Errors

The operator returns an error if the selected columns ( idColumn and valueColumn) do not exist or valueColumn is not numeric.

Notes

The operator processes a maximum of 20 different ids. After recognizing more than 20 different ids, the operator ignores the rest.

Parameters

Name	Type	Description	Examples
idColumn	string	The column name of the id attribute (one line per id.)	"id"
valueColumn	string	The column name of the value attribute (y-axis values).	"temperature"

Sources

Name	Type	Description
vector	VectorOperator	An operator that produces vector data.

Examples

{
    "type": "FeatureAttributeValuesOverTime",
    "params": {
        "idColumn": "id",
        "valueColumn": "temperature"
    },
    "sources": {
        "vector": {
            "type": "OgrSource",
            "params": {
                "data": "temperatures"
            }
        }
    }
}