Improve map overlay ergonomics

frontend/src/App.tsx

@@ -389,6 +389,46 @@ function App(): JSX.Element {
 
   const selectedArea = areas.find((area) => area.id === selectedMapAreaId) ?? null
   const activeWorkspaceItem = workspaceNavItems.find((item) => item.key === activeWorkspace) ?? workspaceNavItems[0]
+  const mapLayerSourceLabel = useMemo(() => {
+    if (changeDetectionResult?.geojson) {
+      return 'Change detection'
+    }
+    if (segmentationGeoJson) {
+      return 'Segmentation run'
+    }
+    if (detectionGeoJson) {
+      return 'Detection run'
+    }
+    if (datasetContent && selectedDataset) {
+      return `${selectedDataset.dataset_type} dataset`
+    }
+    return 'No active vector or result layer'
+  }, [changeDetectionResult?.geojson, datasetContent, detectionGeoJson, segmentationGeoJson, selectedDataset])
+  const mapLayerProvenance = useMemo(() => {
+    if (changeDetectionResult?.geojson) {
+      return `source ${changeSourceDatasetId || 'n/a'} -> target ${changeTargetDatasetId || 'n/a'}`
+    }
+    if (segmentationGeoJson) {
+      return selectedSegmentationRunId ? `analysis run ${selectedSegmentationRunId}` : 'segmentation results loaded'
+    }
+    if (detectionGeoJson) {
+      return selectedDetectionRunId ? `analysis run ${selectedDetectionRunId}` : 'detection results loaded'
+    }
+    if (datasetContent && selectedDataset) {
+      return `${selectedDataset.dataset_role ?? 'source'} / ${selectedDataset.source_name ?? selectedDataset.source}`
+    }
+    return 'Open a dataset, detection run, segmentation run or change result to draw it here.'
+  }, [
+    changeDetectionResult?.geojson,
+    changeSourceDatasetId,
+    changeTargetDatasetId,
+    datasetContent,
+    detectionGeoJson,
+    segmentationGeoJson,
+    selectedDataset,
+    selectedDetectionRunId,
+    selectedSegmentationRunId,
+  ])
   const openDatasetInMap = (dataset: DatasetCreateResponse) => {
     if (selectedProjectId) {
       loadDatasetDetails(selectedProjectId, dataset)
@@ -565,6 +605,8 @@ function App(): JSX.Element {
               areaFeatureCollection={areaFeatureCollection}
               mapFeatureCollection={mapFeatureCollection}
               mapLayerLabel={mapLayerLabel}
+              mapLayerSourceLabel={mapLayerSourceLabel}
+              mapLayerProvenance={mapLayerProvenance}
               mapLayerVisible={mapLayerVisible}
               mapLayerOpacity={mapLayerOpacity}
               areaLayerVisible={areaLayerVisible}