La mosaïque d'images Landsat de l'Antarctique (LIMA) est une mosaïque continue et pratiquement sans nuages, créée à partir de scènes Landsat 7 ETM+ traitées.
Les scènes Landsat traitées (16 bits) sont des scènes NLAPS de niveau 1Gt converties en 16 bits, traitées avec correction de l'angle solaire et converties en valeurs de réflectance (Bindschadler 2008).
Chaque scène Landsat est traitée avec des données d'altitude et une correction de l'angle du soleil pour garantir une représentation précise des caractéristiques de surface. L'angle du soleil en Antarctique donne l'impression d'un soleil couchant. En raison du faible angle du soleil, les bords extérieurs du continent apparaissent plus lumineux que les zones plus proches du pôle Sud lorsque Landsat survole l'Antarctique. Les scènes présentent donc des zones claires et sombres.
Les angles de soleil et les ombres incohérents ont été corrigés pour ces scènes. Sans ce processus, la mosaïque produirait un patchwork de scènes, car chaque scène aurait un côté plus clair et un côté plus sombre.
Il s'agit d'une table contenant les métadonnées de la collection d'images USGS/LIMA/SR.
Schéma de la table
Schéma de table
Nom
Type
Description
ACQ_DATE
STRING
Date d'acquisition au format AAAA-MM-JJ
CHEMIN
INT
Chemin d'accès au WRS
POLY_ID
INT
Identifiant unique attribué à un polygone
Reste du monde
INT
Ligne WRS
SCENE_ID
STRING
ID de la scène
CAPTEUR
STRING
Capteur
ESPACE
STRING
Nom du satellite utilisé pour collecter les données
Conditions d'utilisation
Conditions d'utilisation
Ces images appartiennent au domaine public et peuvent être utilisées librement et sans mention de source. Toutefois, nous vous serions reconnaissants de mentionner le projet LIMA (Landsat Image Mosaic of Antarctica).
Citations
Citations :
Bindschadler, R., Vornberger, P., Fleming, A., Fox, A., Mullins, J.,
Binnie, D., Paulson, S., Granneman, B., et Gorodetzky, D., 2008,
The Landsat Image Mosaic of Antarctica, Remote Sensing of
Environment, 112, pp. 4214-4226.
PDF
La mosaïque d'images Landsat de l'Antarctique (LIMA) est une mosaïque homogène et pratiquement sans nuages, créée à partir de scènes Landsat 7 ETM+ traitées. Les scènes Landsat traitées (16 bits) sont des scènes NLAPS de niveau 1Gt converties en 16 bits, traitées avec correction de l'angle solaire et converties en valeurs de réflectance (Bindschadler 2008). Chaque scène Landsat est…
[null,null,[],[[["\u003cp\u003eUSGS LIMA is a cloud-free Landsat 7 ETM+ mosaic of Antarctica, created from scenes processed to reflectance values with sun-angle correction.\u003c/p\u003e\n"],["\u003cp\u003eThis dataset provides a table containing metadata for the USGS/LIMA/SR Image Collection, including acquisition date, sensor, and scene ID.\u003c/p\u003e\n"],["\u003cp\u003eLIMA data covers the period from June 30, 1999, to September 4, 2002, and is freely available for use without acknowledgment.\u003c/p\u003e\n"],["\u003cp\u003eEach Landsat scene in the mosaic was individually processed using elevation data and sun-angle correction to ensure accurate representation of surface features.\u003c/p\u003e\n"],["\u003cp\u003eThe metadata table schema includes fields such as acquisition date, WRS path/row, polygon ID, scene ID, sensor, and satellite name.\u003c/p\u003e\n"]]],["The Landsat Image Mosaic of Antarctica (LIMA), provided by USGS, is a cloudless mosaic from processed Landsat 7 ETM+ scenes. Data, available from 1999-06-30 to 2002-09-04, are level 1Gt NLAPS scenes converted to 16-bit reflectance values with sun-angle correction. Metadata for the collection can be accessed via `ee.FeatureCollection(\"USGS/LIMA/SR_METADATA\")` in Earth Engine, providing acquisition date, path, row, scene ID, sensor, and satellite information. These images are public domain.\n"],null,["# Landsat Image Mosaic of Antarctica (LIMA) - Processed Landsat Scenes (16 bit) Metadata\n\nDataset Availability\n: 1999-06-30T00:00:00Z--2002-09-04T00:00:00Z\n\nDataset Provider\n:\n\n\n [USGS](https://lima.usgs.gov/index.php)\n\nTags\n:\n[antarctica](/earth-engine/datasets/tags/antarctica) [ice](/earth-engine/datasets/tags/ice) [landsat-derived](/earth-engine/datasets/tags/landsat-derived) [lima](/earth-engine/datasets/tags/lima) [mosaic](/earth-engine/datasets/tags/mosaic) [satellite-imagery](/earth-engine/datasets/tags/satellite-imagery) [sr](/earth-engine/datasets/tags/sr) [table](/earth-engine/datasets/tags/table) [usgs](/earth-engine/datasets/tags/usgs) \n\n#### Description\n\nThe Landsat Image Mosaic of Antarctica (LIMA) is a seamless\nand virtually cloudless mosaic created from processed\nLandsat 7 ETM+ scenes.\n\nProcessed Landsat Scenes (16 bit) are Level 1Gt NLAPS\nscenes converted to 16 bit, processed with sun-angle\ncorrection, and converted to reflectance values\n([Bindschadler 2008](https://lima.usgs.gov/LIMA_paper.pdf)).\n\nEach Landsat scene is processed with elevation\ndata and sun-angle correction to ensure surface features\nwere accurately represented. The sun's angle in Antarctica\ngives the appearance of a setting sun. Because of the low\nsun angle, as Landsat passes over Antarctica, the outer\nedges of the continent appear brighter than areas closer\nto the South Pole, so scenes have bright and dark areas.\nInconsistent sun angles and shadows where corrected for\nthese scenes. Without this process, mosaicking would produce\na patchwork of scenes since each scene would have a brighter\nand a darker side.\n\nThis is a table which contains metadata for the Image Collection\n[USGS/LIMA/SR](/earth-engine/datasets/catalog/USGS_LIMA_SR)\n\n### Table Schema\n\n**Table Schema**\n\n| Name | Type | Description |\n|----------|--------|-------------------------------------------|\n| ACQ_DATE | STRING | Acquisition date in YYYY-MM-DD format |\n| PATH | INT | WRS path |\n| POLY_ID | INT | Unique ID assigned to a polygon |\n| ROW | INT | WRS row |\n| SCENE_ID | STRING | Scene ID |\n| SENSOR | STRING | Sensor |\n| SPACE | STRING | Name of the satellite used to gather data |\n\n### Terms of Use\n\n**Terms of Use**\n\nThese images are in the public domain and can be used freely\nand without acknowledgement. However, credit to the Landsat\nImage Mosaic of Antarctica (LIMA) Project is greatly appreciated.\n\n### Citations\n\nCitations:\n\n- Bindschadler, R., Vornberger, P., Fleming, A., Fox, A., Mullins, J.,\n Binnie, D., Paulson, S., Granneman, B., and Gorodetzky, D., 2008,\n The Landsat Image Mosaic of Antarctica, Remote Sensing of\n Environment, 112, pp. 4214-4226.\n [PDF](https://lima.usgs.gov/LIMA_paper.pdf)\n\n### Explore with Earth Engine\n\n| **Important:** Earth Engine is a platform for petabyte-scale scientific analysis and visualization of geospatial datasets, both for public benefit and for business and government users. Earth Engine is free to use for research, education, and nonprofit use. To get started, please [register for Earth Engine access.](https://console.cloud.google.com/earth-engine)\n\n### Code Editor (JavaScript)\n\n```javascript\nvar dataset = ee.FeatureCollection('USGS/LIMA/SR_METADATA');\n\n// Calculate the age of each feature by subtracting\n// the acquisition date from \"today\".\nvar feature_ages = dataset.map(\n function(feature) {\n var today = ee.Date.fromYMD(2024, 1, 12);\n var acq_date = ee.Date.parse(\n 'yyyy-MM-dd', feature.get('ACQ_DATE'));\n var diff = today.difference(acq_date, 'day');\n return feature.set({'ACQ_AGE': diff});\n }\n);\n\n// Reduce by calculating the smallest ACQ_AGE,\n// which gives the most recent acquisition date for\n// that area.\nvar reduced_ages = feature_ages.reduceToImage({\n properties: ['ACQ_AGE'],\n reducer: ee.Reducer.min()\n});\n\nvar reduced_ages_vis = {\n min: 6000,\n max: 9000,\n palette: ['00ff00', 'ff0000'],\n};\n\nvar lon = -43.6;\nvar lat = -74.2;\nvar gray = 150;\nvar background = ee.Image.rgb(gray, gray, gray).visualize({min: 0, max: 255});\n\nMap.setCenter(lon, lat, 2);\nMap.addLayer(\n reduced_ages,\n reduced_ages_vis,\n 'Acquisition Age');\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/USGS/USGS_LIMA_SR_METADATA) \n[Landsat Image Mosaic of Antarctica (LIMA) - Processed Landsat Scenes (16 bit) Metadata](/earth-engine/datasets/catalog/USGS_LIMA_SR_METADATA) \nThe Landsat Image Mosaic of Antarctica (LIMA) is a seamless and virtually cloudless mosaic created from processed Landsat 7 ETM+ scenes. Processed Landsat Scenes (16 bit) are Level 1Gt NLAPS scenes converted to 16 bit, processed with sun-angle correction, and converted to reflectance values (Bindschadler 2008). Each Landsat scene is ... \nUSGS/LIMA/SR_METADATA, antarctica,ice,landsat-derived,lima,mosaic,satellite-imagery,sr,table,usgs \n1999-06-30T00:00:00Z/2002-09-04T00:00:00Z \n-90 -180 -55 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [](https://doi.org/https://lima.usgs.gov/index.php)\n- [](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/USGS_LIMA_SR_METADATA)"]]
