{"agent_hint":"Polygon aggregation: when a place name resolves to a feature with extent (airport, park, lake, region), the boring endpoint fans out to `polygon.sample_cells` and returns mean/median/min/max/std per band (mode + class distribution for categorical bands like esa_worldcover.lc_2021). Pass `n_cells:1` to force a single-cell read at the centroid; use POST /v1/recall_polygon for raw per-cell facts.","aggregator":"mean","band":"indices.ndvi","band_metadata":{"description":"Three optical-index scalars derived from Sentinel-2 L2A: NDVI, NDRE, NDMI. The most-pulled vegetation surface — these are what algorithms like `flood_risk@2`, `crop_stress@1`, and `irrigation_demand@1` compose.","dimension_description":"Normalised Difference Vegetation Index","dimension_index":0,"formula":"NDVI = (B08 − B04) / (B08 + B04), each band first scaled to reflectance as DN * 1e-4 in f64, applied per band before the ratio. Folding the scaling through the ratio is algebraically equal but can differ in the last bits.","inherited_from_cube_band":"indices","interpretation":"NDVI < 0 = water / snow; 0 – 0.2 = bare soil / urban; 0.2 – 0.5 = sparse / stressed vegetation; 0.5 – 0.8 = healthy crops / shrub; > 0.8 = dense closed canopy. NDMI tracks canopy water content (negative = dry, positive = moist). NDRE is more sensitive to chlorophyll than NDVI and saturates later — preferred for in-season nitrogen monitoring.","pitfalls":"Read `surface_class` on the fact before the value. It carries the per-pixel Sentinel-2 SCL class the responder actually probed at this cell (`scl`, `label`, `vegetation_valid`) and answers a question `confidence` does not: confidence scores radiometric cleanliness, so a snow-covered field in January is a clean pixel and scores 0.95 while the NDVI on it measures snow, not vegetation. `vegetation_valid: false` (snow, water, shadow) means the number is real but is not a vegetation reading. Prefer this over the scene-level `weather.cloud_cover` / `cloud_pct` proxies: those describe the whole scene, `surface_class` describes this pixel. Absent when the SCL band could not be read, in which case confidence falls back to scene-level cloud cover and the scene-level proxies are all there is. NDVI saturates above ~0.85 (use NDRE / `geotessera` for dense canopies).","provenance":{"class":"deterministic_index","deterministic":true,"tamper_evidence":"recomputable_from_source","trust_rank":3},"references":"Tucker 1979 (NDVI); Gitelson & Merzlyak 1994 (NDRE); Gao 1996 (NDMI / NDWI); Xu 2006 (MNDWI = (B03-B11)/(B03+B11)); Key & Benson 2006 (NBR = (B08-B12)/(B08+B12)); Hall et al. 1995 (NDSI = (B03-B11)/(B03+B11)); Zha et al. 2003 (NDBI = (B11-B08)/(B11+B08)); Rikimaru et al. 2002 (BSI = ((B11+B04)-(B08+B02))/((B11+B04)+(B08+B02))); Hardisky et al. 1983 (NDWI_Gao = (B03-B08)/(B03+B08), the leaf-water-content form used by the algal-bloom water gate)","units":"unitless [-1, +1]","value_range":[-1.0,1.0]},"captured_at_range":["2026-08-10T21:05:40Z","2026-08-10T21:05:41Z"],"cell_dedupe_m":10,"cold_cells_skipped":8,"cold_cells_skipped_note":"8 cold cell(s) were not materialised this request to stay within the latency budget (EMEM_BORING_COLD_CAP=8). They are counted as missing in the aggregate, so `partial` is true. Re-query to warm more, lower n_cells, or query a specific cell for guaranteed coverage.","coverage_fraction":0.5,"data_resolution_m":10,"fact_cids":["vgl7mbfqtyphbab4p2uhvvwg65n3brlycrjvx5o4tems55ruhdta","v4egas6e72lejglgy6wyhzrtlzwawxuw52gsyph6llanhuqqfpga","4pypdujstee2wzaqjegjvhftr6xha4jzea6leweadkksefgf3ova","axkbydzljnfv5vjnyqm3mt52hw7ugsp2axie3a3imf4ohwut2dta","c3zs7zhn4emeko2jsqxwpvvzpwjw3k2akyoj4imfu7fhtvrd3yga","2ytt4xauhdyxy53a6cmauvtcnqo6oqxtmum3ovipehkpldu46tbq","j5tyuehy3mu7o2y4g2cplmxot3ldfk422p3oxzi7jxjdqfxyfh2q","3aq756jqeqwrmoc4o26askzsstmbvcof4jcsuj333s47vgxjdl4q"],"is_exhaustive":false,"kind":"numeric_scalar","lat":22.454227500000002,"lon":-97.98762916666665,"materialize_notes":[{"band":"indices.ndvi","fact_cid":"vgl7mbfqtyphbab4p2uhvvwg65n3brlycrjvx5o4tems55ruhdta","status":"materialized"},{"band":"indices.ndvi","fact_cid":"v4egas6e72lejglgy6wyhzrtlzwawxuw52gsyph6llanhuqqfpga","status":"materialized"},{"band":"indices.ndvi","fact_cid":"4pypdujstee2wzaqjegjvhftr6xha4jzea6leweadkksefgf3ova","status":"materialized"},{"band":"indices.ndvi","fact_cid":"axkbydzljnfv5vjnyqm3mt52hw7ugsp2axie3a3imf4ohwut2dta","status":"materialized"},{"band":"indices.ndvi","fact_cid":"c3zs7zhn4emeko2jsqxwpvvzpwjw3k2akyoj4imfu7fhtvrd3yga","status":"materialized"},{"band":"indices.ndvi","fact_cid":"2ytt4xauhdyxy53a6cmauvtcnqo6oqxtmum3ovipehkpldu46tbq","status":"materialized"},{"band":"indices.ndvi","fact_cid":"j5tyuehy3mu7o2y4g2cplmxot3ldfk422p3oxzi7jxjdqfxyfh2q","status":"materialized"},{"band":"indices.ndvi","fact_cid":"3aq756jqeqwrmoc4o26askzsstmbvcof4jcsuj333s47vgxjdl4q","status":"materialized"}],"n":8,"n_cells_queried":16,"n_cells_returned":8,"n_missing":8,"next":{"deep_recall":"POST /v1/recall {cell:'<cell64>', bands:[…]}","fact_dereference":"GET /v1/facts/{fact_cid}","raw_per_cell":"POST /v1/recall_polygon {polygon_bbox:{min_lat:22.321552276611328,max_lat:22.804452896118164,min_lng:-98.34349822998047,max_lng:-97.81965637207031}, bands:[…]}","verify_offline":"POST /v1/verify_receipt {receipt}"},"partial":true,"place_label":"Altamira, 28 MX","place_resolution":{"area_km2":2878.201188318513,"confidence_reason":"admin2_region_match","input_query":"Altamira","is_high_confidence":true,"resolved_label":"Altamira, 28 MX","via":"locate:admin2"},"polygon":{"area_km2":2878.201188318513,"bbox":{"max_lat":22.804452896118164,"max_lng":-97.81965637207031,"min_lat":22.321552276611328,"min_lng":-98.34349822998047},"n_sample_cells":16,"sample_cells":["defi.zb4fe.zuxi.vuxE","defi.zb4fe.zuxi.wifi","defi.zb4fe.zuxi.wUlI","defi.zb4fe.zuxi.xEso","defi.zb500.bUgu.vuxE","defi.zb500.bUgu.wifi","defi.zb500.bUgu.wUlI","defi.zb500.bUgu.xEso","defi.zb501.qAyE.vuxE","defi.zb501.qAyE.wifi","defi.zb501.qAyE.wUlI","defi.zb501.qAyE.xEso","defi.zb502.zc6ce.vuxE","defi.zb502.zc6ce.wifi","defi.zb502.zc6ce.wUlI","defi.zb502.zc6ce.xEso"],"scene_overlay_url":"/v1/places/scene_overlay.svg?place=Altamira&band=indices.ndvi&n_cells=16","scene_thumbs_count":16,"source":"overture_division_area"},"responder_pubkey_b32":"5tuqhbx45tcahvycgupww43gssa6sw2cxxzsx5xzp5qz52lcoefq","served_at":"2026-08-10T21:05:41Z","source":"sentinel_s2_l2a","stats":{"cos_lat_weighting_applied":true,"max":0.8466526797634942,"mean":0.4150096971892006,"median":0.6436713017522678,"min":-0.45476973684210525,"n":8,"n_missing":8,"std":0.4568393939329917},"unit":null,"value":0.4150096971892006,"value_per_cell_count":8,"via":"locate:admin2"}