Add comprehensive dataset card with schema

dataset_card.json

@@ -1,19 +1,45 @@
 {
   "dataset_name": "lanternfly_research_dataset",
   "version": "1.0.0",
-  "description": "Human-verified spotted lanternfly sightings with geolocation data",
+  "description": "Human-verified spotted lanternfly sightings with geolocation data for ecological research",
   "created_by": "Lantern Fly Tracker App",
   "total_sightings": 0,
   "last_updated": "2024-01-01T00:00:00Z",
-  "data_fields": {
-    "image": "High-quality photo of verified lanternfly",
-    "latitude": "GPS latitude coordinate",
-    "longitude": "GPS longitude coordinate",
-    "location_name": "Human-readable location description",
-    "username": "Username of person who verified the sighting",
-    "confidence_score": "AI classification confidence (0-1)",
-    "sighting_date": "Date and time of the sighting",
-    "verification_status": "Always 'human_verified' for this dataset",
-    "upload_date": "Date when uploaded to dataset"
-  }
+  "data_schema": {
+    "image": {
+      "type": "file",
+      "description": "High-quality photo of verified spotted lanternfly",
+      "format": "JPEG"
+    },
+    "metadata": {
+      "type": "json",
+      "fields": {
+        "username": "string - Username of person who verified the sighting",
+        "sighting_date": "ISO datetime - When the photo was taken",
+        "upload_date": "ISO datetime - When uploaded to dataset",
+        "latitude": "string - GPS latitude coordinate",
+        "longitude": "string - GPS longitude coordinate",
+        "location_name": "string - Human-readable location description",
+        "confidence_score": "string - AI classification confidence (0-1)",
+        "verification_status": "string - Always 'human_verified'",
+        "dataset_version": "string - Dataset version",
+        "data_source": "string - Source application",
+        "image_filename": "string - Associated image filename",
+        "image_size_bytes": "number - Image file size in bytes"
+      }
+    }
+  },
+  "usage_notes": [
+    "All images are human-verified for accuracy",
+    "GPS coordinates are provided for spatial analysis",
+    "Timestamps enable temporal analysis of spread patterns",
+    "Dataset is automatically updated with new verified sightings"
+  ],
+  "research_applications": [
+    "Ecological distribution modeling",
+    "Invasive species spread analysis",
+    "Machine learning model training",
+    "Conservation planning",
+    "Citizen science validation"
+  ]
 }