Chart Annotation Category

The category on a ChartAnnotation provides a structured way to classify the type of site event documented — for example, "remediation", "regulatory", "sampling", or "infrastructure." Unlike the free-text label and description, category uses a consistent vocabulary so that compliance staff can filter trend charts to show only annotations of a particular type. This is especially useful on sites with long monitoring histories where dozens of annotations may exist: being able to display only regulatory events or only operational changes focuses the chart for specific reporting needs without removing other annotations permanently.