> For the complete documentation index, see [llms.txt](https://docs.geopard.tech/geopard-tutorials/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.geopard.tech/geopard-tutorials/ro/documentatie-api/prezentare-generala-a-cererilor-api-geopard/90.-interogare-obtine-datele-de-imagini-satelitare-dupa-geometrie.md). # 90. Interogare: Obține datele de imagini satelitare după geometrie Preia statistici ale indicelui de vegetație pentru orice geometrie ad-hoc - **nu este necesară o limită de teren înregistrată**. Acest endpoint calculează statistici sumare pentru pixelii din interiorul geometriei tale în timp ce **ignoră pixelii afectați de nori**. În prezent este acceptat pe **Sentinel2 (S2)** , **Landsat (L4/L5/L7/L8/L9)** și **Planet (PS)** furnizori. {% hint style="danger" %} Această pagină urmează tiparele API-ului GeoPard și [autentificarea](https://docs.geopard.tech/geopard-tutorials/api-docs/authorization-apikey-credentials-or-oauth-2.0) utilizată în endpoint-urile GraphQL. {% endhint %} ## Ce poți face * Interoghează **indici de vegetație** pentru **geometrii Point, MultiPoint, Polygon și MultiPolygon** . * Alege imagini **furnizori**: `S2`, `L4`, `L5`, `L7`, `L8`, `L9`, `PS`. * Obține **rezultate** datate per achiziție cu: * `fără nori` - fracțiunea geometriei tale care este fără nori, interval de valori de la 0 la 1, unde 1 înseamnă complet fără nori. * `value` - statistici pentru indicele selectat calculate **doar** pe pixelii fără nori, include `min`, `max`, `avg`, `mdn`, `var`, `std`. * Opțional furnizează **intervale** un tablou de intervale de valori ale indicelui pentru calcularea statisticilor de acoperire. Când este furnizat, răspunsul va include un `intervale` câmp care arată ce procent din suprafață se încadrează în fiecare interval specificat. * **Suprafața ocupată de fiecare culoare/interval** - bazat pe valoarea indicelui (scăzut => ridicat) * **Procentaj de acoperire** - valoare 0..1 per interval reprezentând procentul din suprafață ## Indici suportați `EVI2`, `NDVI`, `RVI`, `LAI`, `OSAVI`, `SAVI`, `GNDVI`, `IPVI`, `GCI`, `WDRVI`, `RCI`, `SBI`, `MCARI1`. Definițiile indicilor urmează [catalogul de indici de vegetație](https://docs.geopard.tech/geopard-tutorials/product-tour-web-app/satellite-monitoring/indices-for-crops-and-soils#vegetation-indices) GeoPard folosit în tot API-ul. ### Parametri de intrare
CâmpTipObligatoriuNote
indexEnum (vezi mai sus)✅Indicele de vegetație de calculat.
furnizori[Provider!]!✅Oricare dintre S2, L4, L5, L7, L8, L9, PS.
startDateString (ISO8601)✅Start inclusiv, de ex. "2025-05-10T00:00:00.000Z".
endDateString (ISO8601)✅Sfârșit exclusiv sau sfârșit inclusiv în funcție de schemă; aliniează-l cu celelalte interogări GeoPard.
geojsonString✅Un GeoJSON stringificat de tip Point / MultiPoint / Polygon / MultiPolygon (WGS84 [lon, lat]). Amintește-ți să escapezi ghilimelele în interiorul stringului.
intervale[[Float!]!]❌Array de [min, max] perechi de intervale de valori ale indicelui pentru calcularea statisticilor de acoperire
## **Ghid de performanță** * Pentru geometriile Polygon/MultiPolygon, păstrează intervalele de date strânse (**\~10–15 zile**) din cauza timpului de procesare. * **Timeout:** 30 s. Folosește mai puține zile și/sau mai puțini furnizori dacă atingi limita. * Pentru Point/MultiPoint, intervalele mai mari sunt de obicei în regulă (punctele sunt ușoare). ## Structura răspunsului ```graphql graphqlCopyEdit{ geojson # ecou al geometriei tale de intrare (stringificat) data: [ { uuid # id scenă raster provider # S2, L8, L9, ... acquisitionDate # ISO8601 cloudfree # fracțiune 0..1 a zonei fără nori value: { index # ex., NDVI min max avg mdn var std } ranges: { value coverage } } ] } ``` ## Exemplul 1: MultiPolygon cu MCARI1 pe S2/L8/L9 într-o fereastră de 5 zile ### Solicitați ```graphql query GetSatelliteImageryDataByMultiPolygon { getSatelliteImageryDataByGeometry( input: { index: MCARI1 # setează indicele aici providers: [S2, L8, L9] # furnizori sateliți startDate: "2025-05-10T00:00:00.000Z" # poligoane: preferă 10–15 zile; timeout 30s endDate: "2025-05-15T00:00:00.000Z" geojson: "{\"type\": \"MultiPolygon\", \"coordinates\":[ [ [ [ 8.09058546, 50.21774961 ], [ 8.09291004, 50.21836077 ], [ 8.09328559, 50.21844893 ], [ 8.09341412, 50.21777585 ], [ 8.09342329, 50.21768228 ], [ 8.09342736, 50.21748691 ], [ 8.09342239, 50.21741988 ], [ 8.09331503, 50.2169872 ], [ 8.09327725, 50.21680672 ], [ 8.0932114, 50.21679383 ], [ 8.09307662, 50.216784 ], [ 8.09268795, 50.21672443 ], [ 8.09256905, 50.21670175 ], [ 8.09160986, 50.21647789 ], [ 8.09153097, 50.21647138 ], [ 8.09144745, 50.216479 ], [ 8.09128792, 50.21653615 ], [ 8.09124139, 50.21654808 ], [ 8.09119362, 50.21655407 ], [ 8.09085379, 50.21653536 ], [ 8.09039423, 50.21649463 ], [ 8.09006609, 50.21646137 ], [ 8.08994025, 50.21644261 ], [ 8.08956206, 50.21636986 ], [ 8.08937343, 50.21632184 ], [ 8.08881276, 50.21616093 ], [ 8.08860924, 50.21608589 ], [ 8.08848952, 50.21605007 ], [ 8.08841856, 50.21616403 ], [ 8.08836721, 50.2162167 ], [ 8.08830625, 50.21626762 ], [ 8.08801583, 50.21648103 ], [ 8.08783363, 50.21660479 ], [ 8.08757577, 50.21677569 ], [ 8.08741435, 50.21686857 ], [ 8.08769592, 50.21696741 ], [ 8.08853411, 50.21720846 ], [ 8.08965086, 50.2174967 ], [ 8.09058546, 50.21774961 ] ] ] ]}" } ) { geojson data { uuid provider acquisitionDate cloudfree # 0..1 value { # statistici calculate doar pe pixelii fără nori index min max avg mdn var std } } } } ``` ### Răspuns ```json { "data": { "getSatelliteImageryDataByGeometry": { "geojson": "\"{\\\"type\\\": \\\"MultiPolygon\\\", \\\"coordinates\\\": [[[[8.09058546, 50.21774961], [8.09291004, 50.21836077], [8.09328559, 50.21844893], [8.09341412, 50.21777585], [8.09342329, 50.21768228], [8.09342736, 50.21748691], [8.09342239, 50.21741988], [8.09331503, 50.2169872], [8.09327725, 50.21680672], [8.0932114, 50.21679383], [8.09307662, 50.216784], [8.09268795, 50.21672443], [8.09256905, 50.21670175], [8.09160986, 50.21647789], [8.09153097, 50.21647138], [8.09144745, 50.216479], [8.09128792, 50.21653615], [8.09124139, 50.21654808], [8.09119362, 50.21655407], [8.09085379, 50.21653536], [8.09039423, 50.21649463], [8.09006609, 50.21646137], [8.08994025, 50.21644261], [8.08956206, 50.21636986], [8.08937343, 50.21632184], [8.08881276, 50.21616093], [8.08860924, 50.21608589], [8.08848952, 50.21605007], [8.08841856, 50.21616403], [8.08836721, 50.2162167], [8.08830625, 50.21626762], [8.08801583, 50.21648103], [8.08783363, 50.21660479], [8.08757577, 50.21677569], [8.08741435, 50.21686857], [8.08769592, 50.21696741], [8.08853411, 50.21720846], [8.08965086, 50.2174967], [8.09058546, 50.21774961]]]]}\"", "data": [ { "uuid": "16c45077-3138-5a9a-9947-d9e54ea77e38", "provider": "S2", "acquisitionDate": "2025-05-13T10:37:03.661000+00:00", "cloudfree": 1, "value": { "index": "MCARI1", "min": 3026.88, "max": 6452.881, "avg": 5020.917, "mdn": 5086.56, "var": 437905.281, "std": 661.744 } }, { "uuid": "cf5d9e51-c0db-5e02-bf97-35c3e7a0fe07", "provider": "S2", "acquisitionDate": "2025-05-13T10:47:13.154000+00:00", "cloudfree": 1, "value": { "index": "MCARI1", "min": 3441.96, "max": 6722.04, "avg": 5333.138, "mdn": 5403.36, "var": 372277.75, "std": 610.146 } }, { "uuid": "de9b6b8a-a195-5694-98a0-f17e8122855d", "provider": "S2", "acquisitionDate": "2025-05-11T10:47:17.500000+00:00", "cloudfree": "0.5547445255474452", "value": { "index": "MCARI1", "min": 3438.96, "max": 6495.96, "avg": 5176.501, "mdn": 5181, "var": 377633.031, "std": 614.519 } }, { "uuid": "917b3657-3ddc-5f43-b39f-5d8493282bde", "provider": "S2", "acquisitionDate": "2025-05-10T10:37:15.656000+00:00", "cloudfree": 1, "value": { "index": "MCARI1", "min": 3395.88, "max": 6272.881, "avg": 4975.816, "mdn": 4999.56, "var": 333405.031, "std": 577.412 } }, { "uuid": "3fc7ed30-677a-5430-a10b-3490d903616c", "provider": "L8", "acquisitionDate": "2025-05-12T10:21:17.302000+00:00", "cloudfree": 1, "value": { "index": "MCARI1", "min": 3171.24, "max": 5361, "avg": 4227.754, "mdn": 4267.68, "var": 261266, "std": 511.142 } }, { "uuid": "f3d1bd32-e3c8-5260-ba4c-d84c6a171986", "provider": "L9", "acquisitionDate": "2025-05-13T10:15:17.115000+00:00", "cloudfree": 1, "value": { "index": "MCARI1", "min": 3353.52, "max": 5451.72, "avg": 4428.534, "mdn": 4491.48, "var": 306042.719, "std": 553.211 } } ] } } } ``` ## Exemplul 2: MultiPoint cu NDVI pe S2/L8/L9 într-o fereastră de 5 zile ### Solicitați ```graphql query GetSatelliteImageryDataByMultiPoint { getSatelliteImageryDataByGeometry( input: { providers: [S2, L8, L9] index: NDVI startDate: "2025-05-10T00:00:00.000Z" # punctele sunt ușoare; ferestre mai mari OK; timeout 30s endDate: "2025-05-15T00:00:00.000Z" geojson: "{\"type\": \"MultiPoint\", \"coordinates\": [[8.088754, 50.216859],[8.092651, 50.216905],[ 8.090799, 50.217442]]}" } ) { geojson data { uuid provider acquisitionDate fără nori value { index min max avg mdn var std } } } } ``` ### Răspuns ```json { "data": { "getSatelliteImageryDataByGeometry": { "geojson": "\"{\\\"type\\\": \\\"MultiPoint\\\", \\\"coordinates\\\": [[8.088754, 50.216859], [8.092651, 50.216905], [8.090799, 50.217442]]}\"", "data": [ { "uuid": "cf5d9e51-c0db-5e02-bf97-35c3e7a0fe07", "provider": "S2", "acquisitionDate": "2025-05-13T10:47:13.154000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.712, "max": 0.873, "avg": 0.815, "mdn": 0.824, "var": 0.002, "std": 0.041 } }, { "uuid": "16c45077-3138-5a9a-9947-d9e54ea77e38", "provider": "S2", "acquisitionDate": "2025-05-13T10:37:03.661000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.642, "max": 0.856, "avg": 0.779, "mdn": 0.794, "var": 0.003, "std": 0.055 } }, { "uuid": "de9b6b8a-a195-5694-98a0-f17e8122855d", "provider": "S2", "acquisitionDate": "2025-05-11T10:47:17.500000+00:00", "cloudfree": "0.6363636363636364", "value": { "index": "NDVI", "min": 0.762, "max": 0.857, "avg": 0.826, "mdn": 0.83, "var": 0.001, "std": 0.029 } }, { "uuid": "917b3657-3ddc-5f43-b39f-5d8493282bde", "provider": "S2", "acquisitionDate": "2025-05-10T10:37:15.656000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.667, "max": 0.854, "avg": 0.79, "mdn": 0.802, "var": 0.002, "std": 0.048 } }, { "uuid": "3fc7ed30-677a-5430-a10b-3490d903616c", "provider": "L8", "acquisitionDate": "2025-05-12T10:21:17.302000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.746, "max": 0.87, "avg": 0.814, "mdn": 0.833, "var": 0.002, "std": 0.039 } }, { "uuid": "f3d1bd32-e3c8-5260-ba4c-d84c6a171986", "provider": "L9", "acquisitionDate": "2025-05-13T10:15:17.115000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.707, "max": 0.85, "avg": 0.795, "mdn": 0.813, "var": 0.002, "std": 0.05 } } ] } } } ``` ## Exemplul 3: MultiPolygon cu NDVI pe S2/L8/L9 cu intervale într-o fereastră de 5 zile ### Solicitați ```graphql query GetSatelliteImageryDataByMultiPolygon { getSatelliteImageryDataByGeometry( input: { index: NDVI # setează indicele aici providers: [S2, L8, L9] # furnizori sateliți startDate: "2025-05-10T00:00:00.000Z" # poligoane: preferă 10–15 zile; timeout 30s endDate: "2025-05-15T00:00:00.000Z" geojson: "{\"type\": \"MultiPolygon\", \"coordinates\":[ [ [ [ 8.09058546, 50.21774961 ], [ 8.09291004, 50.21836077 ], [ 8.09328559, 50.21844893 ], [ 8.09341412, 50.21777585 ], [ 8.09342329, 50.21768228 ], [ 8.09342736, 50.21748691 ], [ 8.09342239, 50.21741988 ], [ 8.09331503, 50.2169872 ], [ 8.09327725, 50.21680672 ], [ 8.0932114, 50.21679383 ], [ 8.09307662, 50.216784 ], [ 8.09268795, 50.21672443 ], [ 8.09256905, 50.21670175 ], [ 8.09160986, 50.21647789 ], [ 8.09153097, 50.21647138 ], [ 8.09144745, 50.216479 ], [ 8.09128792, 50.21653615 ], [ 8.09124139, 50.21654808 ], [ 8.09119362, 50.21655407 ], [ 8.09085379, 50.21653536 ], [ 8.09039423, 50.21649463 ], [ 8.09006609, 50.21646137 ], [ 8.08994025, 50.21644261 ], [ 8.08956206, 50.21636986 ], [ 8.08937343, 50.21632184 ], [ 8.08881276, 50.21616093 ], [ 8.08860924, 50.21608589 ], [ 8.08848952, 50.21605007 ], [ 8.08841856, 50.21616403 ], [ 8.08836721, 50.2162167 ], [ 8.08830625, 50.21626762 ], [ 8.08801583, 50.21648103 ], [ 8.08783363, 50.21660479 ], [ 8.08757577, 50.21677569 ], [ 8.08741435, 50.21686857 ], [ 8.08769592, 50.21696741 ], [ 8.08853411, 50.21720846 ], [ 8.08965086, 50.2174967 ], [ 8.09058546, 50.21774961 ] ] ] ]}" ranges: [ [0.0, 0.5], [0.5, 0.55], [0.55, 0.6], [0.6, 0.65], [0.65, 0.7], [0.7, 0.75], [0.75, 0.8], [0.8, 0.85], [0.85, 0.9] ] } ) { geojson data { uuid provider acquisitionDate cloudfree # 0..1 value { # statistici calculate doar pe pixelii fără nori index min max avg mdn var std } ranges { value coverage # 0..1 } } } } ``` ### Răspuns ```json { "data": { "getSatelliteImageryDataByGeometry": { "geojson": "{\"type\":\"MultiPolygon\",\"coordinates\":[[[[8.09058546,50.21774961],[8.09291004,50.21836077],[8.09328559,50.21844893],[8.09341412,50.21777585],[8.09342329,50.21768228],[8.09342736,50.21748691],[8.09342239,50.21741988],[8.09331503,50.2169872],[8.09327725,50.21680672],[8.0932114,50.21679383],[8.09307662,50.216784],[8.09268795,50.21672443],[8.09256905,50.21670175],[8.09160986,50.21647789],[8.09153097,50.21647138],[8.09144745,50.216479],[8.09128792,50.21653615],[8.09124139,50.21654808],[8.09119362,50.21655407],[8.09085379,50.21653536],[8.09039423,50.21649463],[8.09006609,50.21646137],[8.08994025,50.21644261],[8.08956206,50.21636986],[8.08937343,50.21632184],[8.08881276,50.21616093],[8.08860924,50.21608589],[8.08848952,50.21605007],[8.08841856,50.21616403],[8.08836721,50.2162167],[8.08830625,50.21626762],[8.08801583,50.21648103],[8.08783363,50.21660479],[8.08757577,50.21677569],[8.08741435,50.21686857],[8.08769592,50.21696741],[8.08853411,50.21720846],[8.08965086,50.2174967],[8.09058546,50.21774961]]]]}", "data": [ { "uuid": "cf5d9e51-c0db-5e02-bf97-35c3e7a0fe07", "provider": "S2", "acquisitionDate": "2025-05-13T10:47:13.154000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.625, "max": 0.873, "avg": 0.795, "mdn": 0.808, "var": 0.003, "std": 0.051 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0 }, { "value": [0.55, 0.6], "coverage": 0 }, { "value": [0.6, 0.65], "coverage": 0.0089 }, { "value": [0.65, 0.7], "coverage": 0.0514 }, { "value": [0.7, 0.75], "coverage": 0.1288 }, { "value": [0.75, 0.8], "coverage": 0.2603 }, { "value": [0.8, 0.85], "coverage": 0.4575 }, { "value": [0.85, 0.9], "coverage": 0.0932 } ] }, { "uuid": "917b3657-3ddc-5f43-b39f-5d8493282bde", "provider": "S2", "acquisitionDate": "2025-05-10T10:37:15.656000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.585, "max": 0.854, "avg": 0.768, "mdn": 0.78, "var": 0.003, "std": 0.056 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0 }, { "value": [0.55, 0.6], "coverage": 0.0014 }, { "value": [0.6, 0.65], "coverage": 0.0342 }, { "value": [0.65, 0.7], "coverage": 0.1205 }, { "value": [0.7, 0.75], "coverage": 0.161 }, { "value": [0.75, 0.8], "coverage": 0.3233 }, { "value": [0.8, 0.85], "coverage": 0.3479 }, { "value": [0.85, 0.9], "coverage": 0.0116 } ] }, { "uuid": "16c45077-3138-5a9a-9947-d9e54ea77e38", "provider": "S2", "acquisitionDate": "2025-05-13T10:37:03.661000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.548, "max": 0.856, "avg": 0.756, "mdn": 0.769, "var": 0.004, "std": 0.061 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0.0021 }, { "value": [0.55, 0.6], "coverage": 0.011 }, { "value": [0.6, 0.65], "coverage": 0.05 }, { "value": [0.65, 0.7], "coverage": 0.1198 }, { "value": [0.7, 0.75], "coverage": 0.2231 }, { "value": [0.75, 0.8], "coverage": 0.295 }, { "value": [0.8, 0.85], "coverage": 0.295 }, { "value": [0.85, 0.9], "coverage": 0.0041 } ] }, { "uuid": "de9b6b8a-a195-5694-98a0-f17e8122855d", "provider": "S2", "acquisitionDate": "2025-05-11T10:47:17.500000+00:00", "cloudfree": 0.6067415730337079, "value": { "index": "NDVI", "min": 0.613, "max": 0.865, "avg": 0.782, "mdn": 0.793, "var": 0.003, "std": 0.054 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0 }, { "value": [0.55, 0.6], "coverage": 0 }, { "value": [0.6, 0.65], "coverage": 0.0311 }, { "value": [0.65, 0.7], "coverage": 0.0377 }, { "value": [0.7, 0.75], "coverage": 0.1964 }, { "value": [0.75, 0.8], "coverage": 0.3097 }, { "value": [0.8, 0.85], "coverage": 0.3541 }, { "value": [0.85, 0.9], "coverage": 0.071 } ] }, { "uuid": "3fc7ed30-677a-5430-a10b-3490d903616c", "provider": "L8", "acquisitionDate": "2025-05-12T10:21:17.302000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.619, "max": 0.87, "avg": 0.781, "mdn": 0.793, "var": 0.003, "std": 0.055 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0 }, { "value": [0.55, 0.6], "coverage": 0 }, { "value": [0.6, 0.65], "coverage": 0.0098 }, { "value": [0.65, 0.7], "coverage": 0.0784 }, { "value": [0.7, 0.75], "coverage": 0.201 }, { "value": [0.75, 0.8], "coverage": 0.2451 }, { "value": [0.8, 0.85], "coverage": 0.3873 }, { "value": [0.85, 0.9], "coverage": 0.0784 } ] }, { "uuid": "f3d1bd32-e3c8-5260-ba4c-d84c6a171986", "provider": "L9", "acquisitionDate": "2025-05-13T10:15:17.115000+00:00", "cloudfree": 1, "value": { "index": "NDVI", "min": 0.617, "max": 0.85, "avg": 0.769, "mdn": 0.782, "var": 0.003, "std": 0.055 }, "ranges": [ { "value": [0, 0.5], "coverage": 0 }, { "value": [0.5, 0.55], "coverage": 0 }, { "value": [0.55, 0.6], "coverage": 0 }, { "value": [0.6, 0.65], "coverage": 0.0495 }, { "value": [0.65, 0.7], "coverage": 0.0842 }, { "value": [0.7, 0.75], "coverage": 0.203 }, { "value": [0.75, 0.8], "coverage": 0.3069 }, { "value": [0.8, 0.85], "coverage": 0.3465 }, { "value": [0.85, 0.9], "coverage": 0.0099 } ] } ] } } } ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.geopard.tech/geopard-tutorials/ro/documentatie-api/prezentare-generala-a-cererilor-api-geopard/90.-interogare-obtine-datele-de-imagini-satelitare-dupa-geometrie.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.