Upload metadata.json with huggingface_hub

metadata.json

@@ -0,0 +1,33 @@
+{
+  "title": "World Gravity Map 2012 (WGM2012) \u2014 Modernized GeoParquet (Bouguer + Free-air)",
+  "source": "Bureau Gravim\u00e9trique International (BGI), accessed via NORA Research Lab's AGDFS API",
+  "citation": "Bonvalot, S., Briais, A., Kuhn, M., Peyrefitte, A., Vales, N., Biancale, R., Gabalda, G., Moreaux, G., Reinquin, F. & Sarrailh, M. (2012). Global grids: World Gravity Map (WGM2012). Bureau Gravimetrique International. https://doi.org/10.18168/bgi.23",
+  "native_resolution": "2 arc-minutes x 2 arc-minutes",
+  "crs": "EPSG:4326",
+  "gravity_products": [
+    "Bouguer anomaly (mGal)",
+    "Free-air anomaly, Molodenski (mGal)"
+  ],
+  "known_gaps": "Isostatic anomaly (Airy-Heiskanen, Tc=30km) is part of WGM2012 but not currently exposed by the AGDFS gravity endpoint, so it is not included in this release. Can be added later if that layer becomes available.",
+  "derived_from_models": [
+    "EGM2008",
+    "DTU10",
+    "ETOPO1 (terrain correction)"
+  ],
+  "total_points": 58320000,
+  "value_ranges_mgal": {
+    "bouguer_anomaly_mgal": [
+      -528.96435546875,
+      1005.0118408203125
+    ],
+    "freeair_anomaly_mgal": [
+      -388.63299560546875,
+      990.968017578125
+    ]
+  },
+  "format": "GeoParquet (EPSG:4326 point geometry), partitioned by latitude band",
+  "license": "Academic/research use per BGI terms \u2014 no warranty on accuracy; BGI is not responsible for consequences of use.",
+  "modernized_by": "NORA Research Lab",
+  "modernization_date": "2026-09-01",
+  "pipeline": "AGDFS tiled fetch -> Standardization -> Modern Format -> Validation -> Metadata -> AI/API Ready"
+}