NASADEM adalah pemrosesan ulang data SRTM, dengan akurasi yang ditingkatkan dengan menggabungkan data tambahan dari set data ASTER GDEM, ICESat GLAS, dan PRISM.
Peningkatan pemrosesan yang paling signifikan melibatkan pengurangan ruang kosong melalui peningkatan
pembukaan fase dan penggunaan data ICESat GLAS untuk kontrol.
Ketinggian bilangan bulat dalam file DEM gabungan tanpa celah adalah relatif terhadap geoid EGM96 (sedangkan ketinggian floating-point dalam file DEM khusus SRTM adalah relatif terhadap elipsoid WGS84).
num
0
255
meter
Indeks yang menunjukkan sumber data dan jumlah adegan sumber.
0: Air dalam data badan air SRTM yang dikoreksi
1-23: SRTM 1-23 (maksimum yang diketahui adalah 23)
41-94: PRISM 1-50 (maks. 54 kutub, maks. 37 di tempat lain)
110-160: GDEM3 (jenuh pada 50)
170-220: GDEM2 (jenuh pada 50)
231: SRTMv3 dari GDEM3
232: SRTMv2 dari GDEM3
233: SRTMv2 dari GDEM2
234: SRTM-with-NGA-fill dari GDEM2
241: NED dari GDEM2 (Amerika Serikat)
242: NED dari GDEM3 (Amerika Serikat)
243: CDED dari GDEM2 (Kanada)
244: CDED dari GDEM3 (Kanada)
245: Alaska dari GDEM2 (Alaska)
246: Alaska dari GDEM3 (Alaska)
250: Interpolasi
251: Rata-rata tepi quad di mana dua quad yang berdekatan tidak sesuai (biasanya error GDEM)
255: ERROR (jika NUM TIDAK ADA - tidak ada yang diketahui)
swb
0
255
meter
Data badan air SRTM yang diperbarui
0: Daratan
255: Air
* perkiraan nilai min atau maks
swb Class Table
Nilai
Warna
Deskripsi
0
cokelat
Daratan
255
cadetblue
Air
Persyaratan Penggunaan
Persyaratan Penggunaan
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halaman Kebijakan Data & Informasi NASA.
Kutipan
Kutipan:
NASA JPL (2020). NASADEM Merged DEM Global 1 arc second V001 [Kumpulan data]. NASA EOSDIS Land
Processes DAAC. Diakses pada 30-12-2020 dari doi:10.5067/MEaSUREs/NASADEM/NASADEM_HGT.001
NASADEM adalah pemrosesan ulang data SRTM, dengan akurasi yang lebih baik dengan menggabungkan data tambahan dari set data ASTER GDEM, ICESat GLAS, dan PRISM. Peningkatan pemrosesan yang paling signifikan melibatkan pengurangan kekosongan melalui peningkatan pembukaan fase dan penggunaan data ICESat GLAS untuk kontrol. Dokumentasi: Panduan Pengguna
[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)"]]