O conjunto de dados RGE ALTI descreve o modelo digital de elevação (MDE) da França com o tamanho de pixel de 1 m. Ele foi criado com base em pesquisas obtidas por lidar aéreo ou por correlação de imagens aéreas.
O Lidar foi usado em áreas propensas a inundações, costeiras e grandes florestas. A acurácia vertical do DEM nessas áreas está entre 0,2 m e 0,5 m. O radar foi usado em áreas montanhosas (Alpes, Pirineus, Cévennes, Córsega). Cuidado: em áreas com inclinação acentuada, a precisão vertical média é da ordem de 7 m.
A precisão desses campos foi verificada em várias fontes: as redes rodoviárias e hidrográficas do BD TOPO, terminais geodésicos e pontos calculados no local.
Técnicas de correlação de fotos aéreas são usadas no restante do território.
Em determinadas zonas tratadas por correlação, as medições de campo estão ausentes em grandes extensões devido à presença de vegetação (áreas arborizadas, por exemplo). Os dados de altimetria de 1987 a 2001 (BD Alti) são usados para preencher essas lacunas. A acurácia vertical do DEM nessas áreas está entre 0,5 m e 0,7 m.
No momento, a coleção inclui uma única imagem IGN/RGE_ALTI/1M/2_0/FXX
mostrando a França metropolitana.
Esse conjunto de dados foi preparado e ingerido com o apoio de Guillaume Attard e Julien Bardonnet (AGEOCE).
O processo de preparação está
descrito aqui.
O conjunto de dados RGE ALTI descreve o modelo digital de elevação (MDE) da França com o tamanho de pixel de 1 m. Ele foi criado com base em pesquisas obtidas por lidar aéreo ou por correlação de imagens aéreas. O Lidar foi usado em áreas costeiras, florestais e propensas a inundações. A acurácia vertical do DEM em…
[null,null,[],[[["\u003cp\u003eRGE ALTI provides a 1-meter resolution digital elevation model (DEM) of France, derived from airborne lidar and aerial imagery correlation.\u003c/p\u003e\n"],["\u003cp\u003eThe DEM has varying vertical accuracy, ranging from 0.2m to 0.5m in lidar-covered areas (flood-prone, coastal, and forest) and around 7m in mountainous areas surveyed by radar.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset primarily covers metropolitan France and includes bands for elevation, data source, and distance to the nearest data point.\u003c/p\u003e\n"],["\u003cp\u003eThe data is available from 2009 to 2021 and is accessible through Google Earth Engine.\u003c/p\u003e\n"],["\u003cp\u003eRGE ALTI is licensed under etalab-2.0 and provided by IGN.\u003c/p\u003e\n"]]],[],null,["# RGE ALTI: IGN RGE ALTI Digital Elevation 1m\n\nDataset Availability\n: 2009-01-01T00:00:00Z--2021-01-01T00:00:00Z\n\nDataset Provider\n:\n\n\n [IGN](https://geoservices.ign.fr/rgealti)\n\nTags\n:\n[dem](/earth-engine/datasets/tags/dem) [elevation](/earth-engine/datasets/tags/elevation) [elevation-topography](/earth-engine/datasets/tags/elevation-topography) [geophysical](/earth-engine/datasets/tags/geophysical) \n\n#### Description\n\nThe RGE ALTI dataset describes the digital elevation model (DEM) of France\nwith the pixel size of 1m. It was created from surveys obtained by airborne\nlidar or by correlation of aerial images.\n\nLidar was deployed for flood-prone, coastal, and large forest\nareas. The vertical accuracy of the DEM in these areas is between\n0.2m and 0.5m. Radar was used in mountain areas (Alps, Pyrenees,\nCevennes, Corsica). Caution: in areas with steep slopes, the average\nvertical accuracy is the order of 7m.\n\nThe accuracy of these fields has been checked against various sources:\nthe road and hydrographic networks of the\n[BD TOPO](https://geoservices.ign.fr/bdtopo), geodetic terminals and\npoints calculated on the ground.\n\nAerial photo correlation techniques are used in the rest of the territory.\nOn certain zones treated by correlation, ground measurements are absent\nover large extents due to the presence of vegetation\n(wooded areas, for example). 1987-2001 altimetry data (BD Alti) are used\nto fill these gaps. The vertical accuracy of the DEM on these areas\nis between 0.5m and 0.7m.\n\nCurrently the collection includes a single image IGN/RGE_ALTI/1M/2_0/FXX\nshowing metropolitan France.\n\nThis dataset was prepared and ingested with the support of Guillaume Attard\nand Julien Bardonnet ([AGEOCE](https://www.ageoce.com)).\nThe preparation process is\n[described here](https://medium.com/@gui.attard/pre-processing-the-dem-of-france-rge-alti-5m-for-implementation-into-earth-engine-de9a0778e0d9).\n\nSee also:\n[user's guide](https://geoservices.ign.fr/sites/default/files/2021-07/DC_RGEALTI_2-0.pdf).\n\n### Bands\n\n\n**Pixel Size**\n\n1 meter\n\n**Bands**\n\n| Name | Units | Min | Max | Pixel Size | Description |\n|-------|-------|-------|--------|------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `MNT` | m | -40\\* | 4810\\* | meters | Terrain elevation in meters. |\n| `SRC` | | | | meters | The main source of the data used to calculate the altitude of the node. See Appendix B page 26 in the [user guide](https://geoservices.ign.fr/sites/default/files/2021-07/DC_RGEALTI_2-0.pdf). |\n| `DST` | m | 0 | 255 | meters | The distance in meters between the node and the nearest point used to calculate its altitude. |\n\n\\* estimated min or max value\n\n### Terms of Use\n\n**Terms of Use**\n\n[etalab-2.0](https://spdx.org/licenses/etalab-2.0.html)\n\n### Citations\n\nCitations:\n\n- IGN (2021). RGE ALTI 1m \\[Data set\\]. Accessed 2022-07-01 from\n [IGN website](https://geoservices.ign.fr/rgealti#telechargement1m)\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.Image('IGN/RGE_ALTI/1M/2_0/FXX');\nvar elevation = dataset.select('MNT');\n\nvar elevationVis = {\n min: 0,\n max: 1000,\n palette: ['006600', '002200', 'fff700', 'ab7634', 'c4d0ff', 'ffffff']\n};\n\nMap.addLayer(elevation, elevationVis, 'Elevation');\nMap.setCenter(3, 47, 5);\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/IGN/IGN_RGE_ALTI_1M_2_0) \n[RGE ALTI: IGN RGE ALTI Digital Elevation 1m](/earth-engine/datasets/catalog/IGN_RGE_ALTI_1M_2_0) \nThe RGE ALTI dataset describes the digital elevation model (DEM) of France with the pixel size of 1m. It was created from surveys obtained by airborne lidar or by correlation of aerial images. Lidar was deployed for flood-prone, coastal, and large forest areas. The vertical accuracy of the DEM in ... \nIGN/RGE_ALTI/1M/2_0, dem,elevation,elevation-topography,geophysical \n2009-01-01T00:00:00Z/2021-01-01T00:00:00Z \n41.35 -5.2 51.14 9.85 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [](https://doi.org/https://geoservices.ign.fr/rgealti)\n- [](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/IGN_RGE_ALTI_1M_2_0)"]]
