NASADEM, SRTM verilerinin yeniden işlenmiş halidir. ASTER GDEM, ICESat GLAS ve PRISM veri kümelerinden elde edilen yardımcı verilerle doğruluğu artırılmıştır.
En önemli işleme iyileştirmeleri, geliştirilmiş faz açma ve kontrol için ICESat GLAS verilerini kullanarak boşluk azaltmayı içerir.
Birleştirilmiş boşluksuz DEM dosyalarındaki tam sayı yükseklikler EGM96 jeoidine (yalnızca SRTM içeren DEM dosyalarındaki kayan nokta yükseklikleri ise WGS84 elipsoidine) göre belirlenir.
num
0
255
metre
Veri kaynağını ve kaynak sahnelerin sayısını gösteren dizin.
0: Düzeltilmiş SRTM su kütlesi verilerindeki su
1-23: SRTM 1-23 (bilinen maksimum değer 23'tür)
41-94: PRISM 1-50 (54 maks. kutup, 37 maks. diğer yerler)
110-160: GDEM3 (50'de doygun)
170-220: GDEM2 (50'de doygun)
231: GDEM3'ten SRTMv3
232: SRTMv2 from GDEM3
233: GDEM2'den SRTMv2
234: SRTM-with-NGA-fill from GDEM2
241: NED from GDEM2 (USA)
242: NED from GDEM3 (ABD)
243: CDED from GDEM2 (Kanada)
244: CDED from GDEM3 (Kanada)
245: GDEM2'den Alaska (Alaska)
246: GDEM3'ten Alaska (Alaska)
250: İnterpolasyon
251: İki komşu dörtgenin uyuşmadığı yerlerde dörtgen kenarı ortalaması alındı (genellikle GDEM hatası)
255: HATA (NUM EKSİKSE - bilinen yok)
swb
0
255
metre
Güncellenen SRTM su kütlesi verileri
0: Arazi
255: Su
* tahmini minimum veya maksimum değer
swb Class Table
Değer
Renk
Açıklama
0
brown
Arsa
255
cadetblue
Su
Kullanım Şartları
Kullanım Şartları
Aksi belirtilmediği sürece, NASA tarafından üretilen tüm veriler önceden izin alınmaksızın herhangi bir amaçla kullanılabilir. Daha fazla bilgi ve istisna için NASA Veri ve Bilgi Politikası sayfasını ziyaret edin.
Alıntılar
Alıntılar:
NASA JPL (2020). NASADEM Merged DEM Global 1 arc second V001 [Veri kümesi]. NASA EOSDIS Land
Processes DAAC. 2020-12-30 tarihinde doi:10.5067/MEaSUREs/NASADEM/NASADEM_HGT.001 adresinden erişildi.
NASADEM, SRTM verilerinin yeniden işlenmiş halidir. ASTER GDEM, ICESat GLAS ve PRISM veri kümelerinden alınan yardımcı veriler eklenerek doğruluğu artırılmıştır. En önemli işleme iyileştirmeleri, geliştirilmiş faz açma işlemi ve kontrol için ICESat GLAS verilerinin kullanılmasıyla boşluk azaltmayı içerir. Belgeler: Kullanıcı Kılavuzu
[null,null,[],[[["\u003cp\u003eNASADEM is a NASA product providing a global Digital Elevation Model (DEM) at 30-meter resolution.\u003c/p\u003e\n"],["\u003cp\u003eIt is derived from SRTM data and enhanced with ASTER GDEM, ICESat GLAS, and PRISM datasets for improved accuracy and void reduction.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset includes elevation, data source index, and updated water body data bands.\u003c/p\u003e\n"],["\u003cp\u003eNASADEM data is freely available for use with proper attribution to NASA JPL.\u003c/p\u003e\n"],["\u003cp\u003eEarth Engine users can access and analyze NASADEM data using the provided code snippet.\u003c/p\u003e\n"]]],["The NASADEM dataset, provided by NASA/USGS/JPL-Caltech, offers reprocessed SRTM elevation data from February 11-22, 2000, with 30-meter pixel resolution. It includes `elevation`, `num` (data source index), and `swb` (water body) bands. NASADEM enhances SRTM by integrating data from ASTER GDEM, ICESat GLAS, and PRISM to reduce data voids and improve accuracy. Data is freely available for any purpose and can be accessed via an Earth Engine snippet and linked JavaScript code.\n"],null,["# NASADEM: NASA 30m Digital Elevation Model\n\nDataset Availability\n: 2000-02-11T00:00:00Z--2000-02-22T00:00:00Z\n\nDataset Provider\n:\n\n\n [NASA / USGS / JPL-Caltech](https://lpdaac.usgs.gov/products/nasadem_hgtv001/)\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) [nasa](/earth-engine/datasets/tags/nasa) [srtm](/earth-engine/datasets/tags/srtm) [topography](/earth-engine/datasets/tags/topography) [usgs](/earth-engine/datasets/tags/usgs) \nnasadem \n\n#### Description\n\nNASADEM is a reprocessing of SRTM data, with improved accuracy by incorporating auxiliary data\nfrom ASTER GDEM, ICESat GLAS, and PRISM datasets.\n\nThe most significant processing improvements involve void reduction through improved\nphase unwrapping and using ICESat GLAS data for control.\n\nDocumentation:\n\n- [User's Guide](https://lpdaac.usgs.gov/documents/592/NASADEM_User_Guide_V1.pdf)\n\n### Bands\n\n\n**Pixel Size**\n\n30 meters\n\n**Bands**\n\n| Name | Units | Min | Max | Pixel Size | Description |\n|-------------|-------|--------|--------|------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `elevation` | m | -512\\* | 8768\\* | meters | Integer heights in the merged void-free DEM files are relative to the EGM96 geoid (whereas the floating-point heights in the SRTM-only DEM files are relative to the WGS84 ellipsoid). |\n| `num` | | 0 | 255 | meters | Index indicating the data source and the number of source scenes. - 0: Water in corrected SRTM water body data - 1-23: SRTM 1-23 (max known is 23) - 41-94: PRISM 1-50 (54 max polar, 37 max elsewhere) - 110-160: GDEM3 (saturated at 50) - 170-220: GDEM2 (saturated at 50) - 231: SRTMv3 from GDEM3 - 232: SRTMv2 from GDEM3 - 233: SRTMv2 from GDEM2 - 234: SRTM-with-NGA-fill from GDEM2 - 241: NED from GDEM2 (USA) - 242: NED from GDEM3 (USA) - 243: CDED from GDEM2 (Canada) - 244: CDED from GDEM3 (Canada) - 245: Alaska from GDEM2 (Alaska) - 246: Alaska from GDEM3 (Alaska) - 250: Interpolation - 251: Quad edge averaged where two neighboring quads disagreed (generally a GDEM error) - 255: ERROR (if NUM IS MISSING - none known to exist) |\n| `swb` | | 0 | 255 | meters | Updated SRTM water body data - 0: Land - 255: Water |\n\n\\* estimated min or max value\n\n**swb Class Table**\n\n| Value | Color | Description |\n|-------|-----------|-------------|\n| 0 | brown | Land |\n| 255 | cadetblue | Water |\n\n### Terms of Use\n\n**Terms of Use**\n\nUnless otherwise noted, all NASA-produced data may be used for any purpose without\nprior permission. For more information and exceptions visit the\n[NASA Data \\& Information Policy page](https://earthdata.nasa.gov/collaborate/open-data-services-and-software/data-information-policy).\n\n### Citations\n\nCitations:\n\n- NASA JPL (2020). NASADEM Merged DEM Global 1 arc second V001 \\[Data set\\]. NASA EOSDIS Land\n Processes DAAC. Accessed 2020-12-30 from [doi:10.5067/MEaSUREs/NASADEM/NASADEM_HGT.001](https://doi.org/10.5067/MEaSUREs/NASADEM/NASADEM_HGT.001)\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\n// Import the dataset and select the elevation band.\nvar dataset = ee.Image('NASA/NASADEM_HGT/001');\nvar elevation = dataset.select('elevation');\n\n// Add a white background image to the map.\nvar background = ee.Image(1);\nMap.addLayer(background, {min: 0, max: 1});\n\n// Set elevation visualization properties.\nvar elevationVis = {\n min: 0,\n max: 2000,\n};\n\n// Set elevation \u003c= 0 as transparent and add to the map.\nMap.addLayer(elevation.updateMask(elevation.gt(0)), elevationVis, 'Elevation');\nMap.setCenter(17.93, 7.71, 2);\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/NASA/NASA_NASADEM_HGT_001) \n[NASADEM: NASA 30m Digital Elevation Model](/earth-engine/datasets/catalog/NASA_NASADEM_HGT_001) \nNASADEM is a reprocessing of SRTM data, with improved accuracy by incorporating auxiliary data from ASTER GDEM, ICESat GLAS, and PRISM datasets. The most significant processing improvements involve void reduction through improved phase unwrapping and using ICESat GLAS data for control. Documentation: User's Guide \nNASA/NASADEM_HGT/001, dem,elevation,elevation-topography,geophysical,nasa,srtm,topography,usgs \n2000-02-11T00:00:00Z/2000-02-22T00:00:00Z \n-56 -180 60 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [](https://doi.org/https://lpdaac.usgs.gov/products/nasadem_hgtv001/)\n- [](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/NASA_NASADEM_HGT_001)"]]
