The ALOS Global Digital Surface Model (AW3D30) is a global dataset generated from images collected using the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) aboard the Advanced Land Observing Satellite (ALOS) from 2006 to 2011. As described by the Japan Aerospace Exploration Agency: The Japan Aerospace Exploration Agency (JAXA) releases the global digital surface model (DSM) dataset with a horizontal resolution of approx. 30-meter mesh (1 arcsec) free of charge. The dataset has been compiled with images acquired by the Advanced Land Observing Satellite "DAICHI" (ALOS). The dataset is published based on the DSM dataset (5-meter mesh version) of the "World 3D Topographic Data", which is the most precise global-scale elevation data at this time, and its elevation precision is also at a world-leading level as a 30-meter mesh version. This dataset is expected to be useful for scientific research, education, as well as the private service sector that uses geospatial information. Version: As of May 24th 2021 OpenTopography is supplying V3.2 (Jan 2021) from: ftp://ftp.eorc.jaxa.jp//pub/ALOS/ext1/AW3D30/release_v2012_single_format/ Data downloaded prior to May 24th 2021 was in format: May 2016: Global terrestrial region (within approx. 82 deg. of N/S latitudes) of Version 1 released (approx. 22,100 tiles) Note: JAXA provides two versions of AW3D30 created from the original 5-meter mesh using different downsampling methods: average (provided here) and median (not available from OpenTopography).

Note: This version of the ALOS World 3D dataset is provided in a WGS84 ellipsoidal vertical datum. This is a non-standard version of the AW3D30 dataset that is often used for InSAR analysis. This dataset was converted from the orthometric version using the EGM96 geoid model available here. For additional conversion details feel free to contact us.

The ALOS Global Digital Surface Model (AW3D30) is a global dataset generated from images collected using the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) aboard the Advanced Land Observing Satellite (ALOS) from 2006 to 2011. As described by the Japan Aerospace Exploration Agency: The Japan Aerospace Exploration Agency (JAXA) releases the global digital surface model (DSM) dataset with a horizontal resolution of approx. 30-meter mesh (1 arcsec) free of charge. The dataset has been compiled with images acquired by the Advanced Land Observing Satellite "DAICHI" (ALOS). The dataset is published based on the DSM dataset (5-meter mesh version) of the "World 3D Topographic Data", which is the most precise global-scale elevation data at this time, and its elevation precision is also at a world-leading level as a 30-meter mesh version. This dataset is expected to be useful for scientific research, education, as well as the private service sector that uses geospatial information.

Version: As of May 24th 2021 OpenTopography is supplying V3.2 (Jan 2021) from:
ftp://ftp.eorc.jaxa.jp//pub/ALOS/ext1/AW3D30/release_v2012_single_format/
Data downloaded prior to May 24th 2021 was in format: May 2016: Global terrestrial region (within approx. 82 deg. of N/S latitudes) of Version 1 released (approx. 22,100 tiles)

Note: JAXA provides two versions of AW3D30 created from the original 5-meter mesh using different downsampling methods: average (provided here) and median (not available from OpenTopography).

ALOS World 3D - 30m (AW3D30) is a global digital surface model (DSM) dataset with a horizontal resolution of approximately 30 meters (1 arcsec mesh). The dataset is based on the DSM dataset (5-meter mesh version) of the World 3D Topographic Data. More details are available in the dataset documentation. This ingested dataset combines data from versions 3.1, 4.0, and 4.1. Version 4.1 (April 2024): This major update released 19,051 tiles covering global regions (excluding Antarctica and Japan). It incorporates new supplementary data for void filling and corrects partial anomalies found in versions 3.1 and 3.2, along with re-filling voids. For specific tile updates in v4.1, please use the v4.1 filter on map tiles or consult the latest format description. Version 4.0 (April 2023): This update released 1,886 tiles, improving low and mid-latitude regions and areas south of 60 degrees latitude. Key changes include: 1. New supplementary data for void filling. 2. Correction of partial anomalies and re-filling of voids (2 tiles). 3. Updated coastlines for regions south of 60 degrees latitude (44 tiles). 4. Disabled Caspian Sea water mask and supplemented with elevation data (54 tiles). 5. Extracted and corrected new partial anomaly areas in South America (1,786 tiles). 6. For detailed tile information for v4.0, please use the v4.0 filter on map tiles or refer to the format description. Version 3.2, released in January 2021, is an improved version created by reconsidering the format in the high latitude area, auxiliary data, and processing method. Different pixel spacing for each latitude zone was adopted at high latitude area. Coastline data, which is one of the auxiliary datasets, was changed, and new supplementary data was used. In addition, as a source data for Japan, AW3D version 3 was also used. Furthermore, the method of detecting anomalous values in the process was improved. Note: See the code example for the recommended way of computing slope. Unlike most DEMs in Earth Engine, this is an image collection due to multiple resolutions of source files that make it impossible to mosaic them into a single asset, so the slope computations need a reprojection. The AW3D DSM elevation is calculated by an image matching process that uses a stereo pair of optical images. Clouds, snow, and ice are automatically identified during processing and applied the mask information. However, mismatched points sometimes remain especially surrounding (or at the edges of) clouds, snow, and ice areas, which cause some height errors in the final DSM.

The ALOS Global Digital Surface Model (AW3D30) is a global dataset generated from images collected using the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) aboard the Advanced Land Observing Satellite (ALOS) from 2006 to 2011. As described by the Japan Aerospace Exploration Agency: The Japan Aerospace Exploration Agency (JAXA) releases the global digital surface model (DSM) dataset with a horizontal resolution of approx. 30-meter mesh (1 arcsec) free of charge. The dataset has been compiled with images acquired by the Advanced Land Observing Satellite "DAICHI" (ALOS). The dataset is published based on the DSM dataset (5-meter mesh version) of the "World 3D Topographic Data", which is the most precise global-scale elevation data at this time, and its elevation precision is also at a world-leading level as a 30-meter mesh version. This dataset is expected to be useful for scientific research, education, as well as the private service sector that uses geospatial information. Version: As of May 24th 2021 OpenTopography is supplying V3.2 (Jan 2021) from: ftp://ftp.eorc.jaxa.jp//pub/ALOS/ext1/AW3D30/release_v2012_single_format/ Data downloaded prior to May 24th 2021 was in format: May 2016: Global terrestrial region (within approx. 82 deg. of N/S latitudes) of Version 1 released (approx. 22,100 tiles) Note: JAXA provides two versions of AW3D30 created from the original 5-meter mesh using different downsampling methods: average (provided here) and median (not available from OpenTopography).

This study developed a method to estimate building height for all of China based on the Advanced Land Observing Satellite (ALOS) World 3D-30 m (AW3D30) DSM and other ancillary data including the Global Artificial Impervious Area (GAIA) dataset, the NASADEM dataset and the Global Roads Inventory Project (GRIP) dataset. The proposed method enabled us to accurately estimate building height with a special slope correction algorithm, improving the accuracy of building height estimation. The outcome of our procedure is a map of building height for China at a spatial resolution of 30 m. Compared to field-measured building height data and reference building height data from Baidu map, results indicate that the proposed method performed well (root mean square error (RMSE) of 4.26 m and 4.98 m, respectively). The new building height map of China contributes to the improved management of urban areas and further studies of urban environments.Reference: https://doi.org/10.1016/j.isprsjprs.2022.01.022.

A dataset of pairs of RGB satellite images and their corresponding DEM images.

ALOS World 3D – 30m‏ (AW3D30) הוא מערך נתונים של מודל דיגיטלי גלובלי של פני השטח (DSM) עם רזולוציה אופקית של כ-30 מטרים (רשת של 1 שניות קשת). מערך הנתונים מבוסס על מערך הנתונים של DSM (גרסת רשת של 5 מטרים) של World 3D Topographic Data. פרטים נוספים זמינים במסמכי התיעוד של מערך הנתונים. מערך הנתונים שעבר הטמעה משללב נתונים מגרסאות 3.1,‏ 4.0 ו-4.1. גרסה 4.1 (אפריל 2024): במסגרת העדכון העיקרי הזה נוספו 19,051 משבצות שכוללות אזורים ברחבי העולם (לא כולל אנטארקטיקה ויפן). הגרסה הזו כוללת נתונים משלימים חדשים למילוי נתונים חסרים, מתקנת חריגות חלקיות שנמצאו בגרסאות 3.1 ו-3.2, וממלאת מחדש נתונים חסרים. כדי לקבל עדכונים ספציפיים של משבצות בגרסה 4.1, צריך להשתמש במסנן v4.1 על משבצות המפה או לעיין בתיאור הפורמט העדכני ביותר. גרסה 4.0 (אפריל 2023): בעדכון הזה נוספו 1,886 משבצות, ששיפרו את האיכות באזורים עם קו הרוחב נמוך ובינוני ובאזורים שמדרום לקו הרוחב 60 מעלות. השינויים העיקריים כוללים: 1. נתונים משלימים חדשים למילוי חוסרים. 2. תיקון של חריגות חלקיות ומילוי מחדש של שטחים ריקים (2 משבצות). 3. קו החוף עודכן באזורים שמדרום לקו הרוחב 60 מעלות (44 משבצות). 4. מסכת המים של הים הכספי מושבתת ומתווספים לה נתוני גובה (54 משבצות). 5. חילוץ ותיקון של אזורים חדשים של חריגות חלקיות בדרום אמריקה (1,786 משבצות). 6. למידע מפורט על המשבצות של גרסה 4.0, אפשר להשתמש במסנן v4.0 על משבצות המפה או לעיין בתיאור הפורמט. גרסה 3.2, שפורסמה בינואר 2021, היא גרסה משופרת שנוצרה על ידי בדיקה מחדש של הפורמט באזורים עם קו הרוחב הגבוה, של הנתונים המשניים ושל שיטת העיבוד. באזורים עם קו הרוחב גבוה, הוחלט להשתמש במרווחים שונים של פיקסלים לכל אזור רוחב. נתוני קו החוף, שהם אחת מקבוצות הנתונים המשניות, השתנו, והשתמשו בנתונים משלימים חדשים. בנוסף, נעשה שימוש גם ב-AW3D גרסה 3 כנתוני מקור ליפן. בנוסף, שיפרנו את השיטה לזיהוי ערכים חריגים בתהליך. הערה: בדוגמה לקוד מוסבר איך מחשבים את השיפוע בצורה המומלצת. בניגוד לרוב ה-DEM ב-Earth Engine, מדובר באוסף תמונות בגלל שיש כמה רזולוציות של קובצי המקור, ולכן אי אפשר ליצור מהם מוזיאה לנכס יחיד. לכן, כדי לחשב את השיפועים צריך לבצע הקרנה מחדש. הגובה של DSM ב-AW3D מחושב באמצעות תהליך התאמת תמונות שמשתמש בזוג תמונות אופטיות סטריאוסקופיות. עננים, שלג וקרח מזוהים באופן אוטומטי במהלך העיבוד, ומידע מהמסכה מוחל עליהם. עם זאת, לפעמים נשארות נקודות לא תואמות, במיוחד סביב עננים, שלג ואזורי קרח (או בקצוות שלהם), שגורמות לשגיאות גובה מסוימות ב-DSM הסופי.

O ALOS World 3D - 30m (AW3D30) é um conjunto de dados de modelo de superfície digital (DSM) global com uma resolução horizontal de aproximadamente 30 metros (1 malha de arco-segundos). O conjunto de dados é baseado no conjunto de dados do DSM (versão de malha de 5 metros) dos Dados topográficos do mundo em 3D. Confira mais detalhes na documentação do conjunto de dados. Esse conjunto de dados ingerido combina dados das versões 3.1, 4.0 e 4.1. Versão 4.1 (abril de 2024): essa atualização importante lançou 19.051 blocos que cobrem regiões globais (exceto Antártida e Japão). Ele incorpora novos dados suplementares para preenchimento de nulos e corrige anomalias parciais encontradas nas versões 3.1 e 3.2, além de preencher novamente os nulos. Para atualizações específicas de blocos na v4.1, use o filtro v4.1 nos blocos do mapa ou consulte a descrição do formato mais recente. Versão 4.0 (abril de 2023): essa atualização lançou 1.886 blocos, melhorando as regiões de baixa e média latitude e as áreas ao sul de 60 graus de latitude. As principais mudanças incluem: 1. Novos dados complementares para preenchimento de nulos. 2. Correção de anomalias parciais e preenchimento de espaços vazios (dois blocos). 3. Atualização das costas para regiões ao sul de 60 graus de latitude (44 blocos). 4. A máscara de água do Mar Cáspio foi desativada e complementada com dados de elevação (54 blocos). 5. Extraímos e corrigimos novas áreas de anomalia parcial na América do Sul (1.786 blocos). 6. Para informações detalhadas sobre os blocos da v4.0, use o filtro v4.0 nos blocos de mapa ou consulte a descrição do formato. A versão 3.2, lançada em janeiro de 2021, é uma versão aprimorada criada ao reconsiderar o formato na área de latitude alta, os dados auxiliares e o método de processamento. O espaçamento de pixels diferente para cada zona de latitude foi adotado na área de latitude alta. Os dados da costa, que são um dos conjuntos de dados auxiliares, foram alterados, e novos dados suplementares foram usados. Além disso, como dados de origem do Japão, a versão 3 do AW3D também foi usada. Além disso, o método de detecção de valores anormais no processo foi melhorado. Observação: confira o exemplo de código para saber a maneira recomendada de calcular a inclinação. Ao contrário da maioria dos DEMs no Earth Engine, essa é uma coleção de imagens devido a várias resoluções de arquivos de origem que impossibilitam a criação de mosaicos em um único recurso. Portanto, as computações de inclinação precisam de uma reprojeção. A elevação do DSM do AW3D é calculada por um processo de correspondência de imagens que usa um par estéreo de imagens ópticas. Nuvens, neve e gelo são identificados automaticamente durante o processamento e aplicam as informações da máscara. No entanto, pontos incompatíveis às vezes permanecem ao redor (ou nas bordas de) nuvens, neve e gelo, o que causa alguns erros de altura no DSM final.

ALOS World 3D - 30m (AW3D30) 是全球數位地表模型(DSM) 資料集，水平解析度約為30 公尺(1 弧秒網格)。這個資料集是以World 3D 地形資料的 DSM 資料集(5 公尺網格版本) 為基礎。如需更多詳細資訊，請參閱資料集說明文件。 這個攝入的資料集結合了3.1、4.0 和 4.1 版的資料。 4.1 版 (2024 年 4 月)：這項重大更新發布了19,051 個資訊方塊，涵蓋全球各個地區(不含南極洲和日本)。它整合了新的補充資料，用於填補空白資料，並修正版本3.1 和 3.2 中發現的部分異常狀況，以及重新填補空白資料。如需v4.1 中的特定圖塊更新，請在地圖圖塊上使用v4.1 篩選器，或參閱最新的格式說明。 版本 4.0 (2023 年 4 月)：這次更新發布了1,886 個圖塊，改善低緯度和中緯度地區，以及緯度60 度以南的地區。 主要異動如下： 1. 新增用於填補空白的補充資料。2. 修正部分異常情形，並重新填入空白區域(2 個圖塊)。3. 更新了南緯60 度 (44 個圖塊) 以南地區的海岸線。4. 停用裏海水遮罩，並補充高程資料(54 個圖塊)。5. 擷取並修正南美洲的新部分異常區域(1,786 個圖塊)。6. 如需v4.0 的詳細資訊方塊資訊，請在地圖資訊方塊上使用v4.0 篩選器，或參閱格式說明。 2021 年 1 月發布的3.2 版是經過改良的版本，我們重新考量高緯度區域的格式、輔助資料和處理方法。在高緯度地區，每個緯度區域採用不同的像素間距。我們變更了海岸線資料(輔助資料集之一)，並使用新的輔助資料。此外，我們也使用AW3D 3 版做為日本的來源資料。此外，我們也改善了在程序中偵測異常值的方法。 注意： 請參閱程式碼範例，瞭解計算斜率的建議方式。與 Earth Engine 中的大多數DEM 不同，由於來源檔案具有多種解析度，因此無法將這些檔案拼接成單一資產，因此坡度運算需要重新投影。AW3D DSM 高度是透過圖像比對程序計算，該程序會使用立體成對的光學圖像。系統會在處理期間自動辨識雲、雪和冰，並套用遮罩資訊。不過，不相符的點有時會保留在雲、雪和冰區的周圍(或邊緣)，導致最終DSM 出現高度錯誤。

Elevation data set from AW3D30 DEM for two location within Nigeria:Lagos state and Abuja

The ALOS Ortho Rectified Image Product (ALOS-ORI) released by the Japan Aerospace Exploration Agency (JAXA) is open to the public. The ALOS-ORI consists of the AVNIR-2 ORI product compiled from images acquired by the Advanced Land Observing Satellite “DAICHI” (ALOS) operated during the period from 2006 to 2011. NASA, in cooperation with JAXA, makes the dataset available through the ASF DAAC. AVNIR-2 Sensor SummaryObservation BandsBand-1 0.42 - 0.50 µmBand-2 0.52 - 0.60 µmBand-3 0.61 - 0.69 µmBand-4 0.76 - 0.89 µmScanning MethodPush BroomS/N>200MTF>0.2Spatial Resolution10 (at Nadir)Swath Width70km (at Nadir) AVNIR-2 Ortho Rectified Image Product The AVNIR-2 ORI product is created from AVNIR-2 1B1 data after stereo matching with reference to the Panchromatic Remote-Sensing Instrument for Stereo Mapping (PRISM) ORI. AW3D30 DSM data, which is created from a PRISM triplet image, is used for the orthorectification processing. If AW3D30 is missing, SRTM (The Shuttle Radar Topography Mission) DSM data is used.* Please refer to the HDR file in the data file to confirm which DSM is used in ORI product creation. The AVNIR-2 ORI product zip file contains the following files:Band-1 0.42 – 0.50 µm (8bit GeoTIFF)Band-2 0.52 – 0.60 µm (8bit GeoTIFF)Band-3 0.61 – 0.69 µm (8bit GeoTIFF)Band-4 0.76 – 0.89 µm (8bit GeoTIFF)Header file (ASCII text) PlatformALOSSensorAdvanced Visible and Near-Infrared Radiometer (AVNIR)-2Observation Period2006-2011Spatial CoverageGlobalCloud Cover30% or lessResolutionapproximately 10m mesh Please refer to AVNIR-2 Ortho Rectified Image Product Format DescriptionJAXA webpage about ALOS Ortho Rectified Image ProductMore about ALOS from JAXAMore about AVNIR-2 from JAXA

Digital Terrain Model for Continental Europe based on the three publicly available Digital Surface Models and predicted using an Ensemble Machine Learning (EML). EML was trainined using GEDI level 2B points (Level 2A; "elev_lowestmode") and ICESat-2 (ATL08; "h_te_mean"): about 9 million points were overlaid vs MERITDEM, AW3D30, GLO-30, EU DEM, GLAD canopy height, tree cover and surface water cover maps, then an ensemble prediction model (mlr package in R) was fitted using random forest, Cubist and GLM, and used to predict most probable terrain height (bare earth). Input layers used to train the EML include:

• "lcv_bare.earth_glcf.landsat": UMD GLAD bare earth estimate for year 2010 based on Landsat time series,
• "dtm_elev.dsm_alos.aw3d": Digital Surface Model based on ALOS AW3D,
• "dtm_canopy.height_glad.umd": UMD GLAD canopy height for 2019 based on GEDI data,
• "dtm_elev.dsm_eudem.eea": Copernicus EU DEM based on the SRTM and ASTER DEMs,
• "hyd_surface.water_jrc.gswe": JRC Global Surface Water Explorer surface water probability based on the Landsat time-series,
• "lcv_landcover.12_pflugmacher2019": land cover map of Europe at 30 based on Pflugmacher et al. (2019),
• "lcv_tree.cover_umd.landsat_2000": forest tree cover for year 2000 based on the Global Forest Change data,
• "lcv_tree.cover_umd.landsat_2010": forest tree cover for year 2010 based on the Global Forest Change data,

Detailed processing steps can be found here. Read more about the processing steps here.

Training data set can be obtained in the file "gedi_elev.lowestmode_2019_eumap.RDS". The initial linear model fitted using the four independent Digital Surface / Digital Terrain models shows:

Residuals:
 Min    1Q  Median    3Q   Max 
-124.627  -1.097  0.973  2.544  59.324 
 
Coefficients:
 Estimate Std. Error t value Pr(>|t|)  
(Intercept)     -1.6220640 0.0032415 -500.4  <2e-16 ***
 eu_dem25m_     -0.1092988 0.0005531 -197.6  <2e-16 ***
 eu_AW3Dv2012_30m_  0.0933774 0.0005957  156.7  <2e-16 ***
 eu_GLO30_30m_    0.2637153 0.0006062  435.1  <2e-16 ***
 eu_MERITv1.0.1_30m_ 0.7496494 0.0005009 1496.6  <2e-16 ***
 ---
 Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 7.059 on 9588230 degrees of freedom
(2046196 observations deleted due to missingness)
Multiple R-squared: 0.9996,  Adjusted R-squared: 0.9996 
F-statistic: 5.343e+09 on 4 and 9588230 DF, p-value: < 2.2e-16

Which show that MERIT DEM (Yamazaki et al., 2019) is the most correlated DEM with GEDI and ICESat-2, most likely because it has been systematically post-processed and majority of canopy problems have been removed. Summary results of the model training (mlr::makeStackedLearner) using all covariates (including canopy height, tree cover, bare earth cover) shows:

Variable: elev_lowestmode.f 
R-square: 1 
Fitted values sd: 333 
RMSE: 6.54 

Ensemble model:
Call:
stats::lm(formula = f, data = d)

Residuals:
   Min    1Q  Median    3Q   Max 
-118.788  -0.871  0.569  1.956 165.119 

Coefficients:
       Estimate Std. Error t value Pr(>|t|)  
(Intercept) -0.198402  0.003045 -65.15  <2e-16 ***
regr.ranger 0.452543  0.001117 405.04  <2e-16 ***
regr.cubist 0.527011  0.001516 347.61  <2e-16 ***
regr.glm   0.020033  0.001217  16.47  <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 6.544 on 9588231 degrees of freedom
Multiple R-squared: 0.9996,  Adjusted R-squared: 0.9996 
F-statistic: 8.29e+09 on 3 and 9588231 DF, p-value: < 2.2e-16

Which indicates that the elevation errors are in average (2/3rd of pixels) between +1-2 m. The variable importance based on Random Forest package ranger shows:

Variable importance:
        variable  importance
4  eu_MERITv1.0.1_30m_ 430641370770
1   eu_AW3Dv2012_30m_ 291483345389
2     eu_GLO30_30m_ 201517488587
3      eu_dem25m_ 132742500162
9 eu_canopy_height_30m_  5148617173
7       bare2010_  2087304901
8    treecover2000_  1761597272
6    treecover2010_  141670217

The output predicted terrain model includes the following two layers:

• "dtm_elev.lowestmode_gedi.eml_mf": mean estimate of the terrain elevation in dm (decimeters) filtered using Gaussian filter and 2x pixel window in SAGA GIS,
• "dtm_elev.lowestmode_gedi.eml_md": standard deviation of the independently fitted stacked predictors quantifying the prediction uncertainty in dm (decimeters),

The predicted elevations are based on the GEDI data hence the reference water surface (WGS84 ellipsoid) is about 43 m higher than the sea water surface for a specific EU country. Before modeling, we have corrected the reference elevations to the Earth Gravitational Model 2008 (EGM2008) by using the 5-arcdegree resolution correction surface (Pavlis et al, 2012).

All GeoTIFFs were prepared using Integer format (elevations rounded to 1 m) and have been converted to Cloud Optimized GeoTIFFs using GDAL.

Disclaimer: The output DTM still shows forest canopy (overestimation of the terrain elevation) and has not been hydrologically corrected for spurious sinks and similar. This data set is continuously updated. To report a bug or suggest an improvement, please visit here. To access DTM derivatives at 30-m, 100-m and 250-m please visit here. To register for updates please subscribe to: https://twitter.com/HarmonizerGeo.

The data is from JAXA earth observation research center（ http://www.eorc.jaxa.jp/ALOS/en/aw3d30/ ）The product is alos World 3D - 30m (aw3d30). Select and download the map by importing the SHP boundary of Sichuan Tibet traffic corridor, and merge it into one by using relevant software. The format is raster data, the spatial resolution is 30m, and the data size is 1.3GB. The DEM data can generate topographic factor data such as slope, aspect and river network by using relevant software. They are the basic data for topographic analysis of Sichuan Tibet traffic corridor, help to understand the geomorphic form of the basin, and are also the key factors for disaster zoning research and risk assessment. The acquisition of high-precision DEM is of great significance for disaster risk management and decision-making level and reducing the loss of major geological disasters.

ALOS World 3D – 30m (AW3D30) là một tập dữ liệu mô hình bề mặt kỹ thuật số (DSM) toàn cầu có độ phân giải theo chiều ngang khoảng 30 mét (lưới 1 giây cung). Tập dữ liệu này dựa trên tập dữ liệu DSM (phiên bản lưới 5 mét) của Dữ liệu địa hình 3D thế giới. Bạn có thể xem thêm thông tin chi tiết trong tài liệu về tập dữ liệu. …

x, latitude of ICESat-2 point

y, longitute of ICESat-2 point

icesat-2, elevation from icesat-2

sigma-icesat-2, error of elevation from icesat-2

date-icesat2, acquiring date of icesat-2 point

dhdx, along track slope of icesat-2 data

dhdx_sigma, error of along track slope of icesat-2 data

elevation range min, the minimum elevation of glaciers where icesat-2 data is located

elevation range med, the median elevation of glaciers where icesat-2 data is located

elevation range max, the maximum elevation of glaciers where icesat-2 data is located

dh, glacier surface elevation change from Shean et al. (2020)

aw3d30, elevation from aw3d30 in EGM96 geoid

srtmgl1, elevation from srtmgl1 in EGM96 geoid

tandem, elevation from TanDEM-X in WGS84 ellipsoid

srtmv41, elevation from srtmv41 in EGM96 geoid

nasadem, elevation from NASADEM in WGS84 ellipsoid

merit, elevation from merit in EGM96 geoid

aw3d30slp, slope from aw3d30

srtmgl1slp, slope from srtmgl1

tandemslp, slope from tandem

srtmv41slp, slope from srtmv41

nasademslp, slope from nasadem

meritslp, slope from merit

aw3d30asp, aspect from aw3d30

srtmgl1asp, aspect from srtmgl1

tandemasp, aspect from tandem

srtmv41asp, aspect from srtmv41

nasademasp, aspect from nasadem

meritasp, aspect from merit

The elevation should be converted using geoidheight function in MATLAB

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Digital Elevation Model (DEM) version 1 (NASADEM_HGT) dataset, which provides global elevation data at 1 arc second spacing.NASADEM data products were derived from original telemetry data from the Shuttle Radar Topography Mission (SRTM), a collaboration between NASA and the National Geospatial-Intelligence Agency (NGA), as well as participation from the German and Italian space agencies. SRTM's primary focus was to generate a near-global DEM of the Earth using radar interferometry. It was a primary component of the payload on space shuttle Endeavour during its STS-99 mission, which was launched on February 11, 2000, and flew for 11 days. In addition to Terra Advanced Spaceborne Thermal and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 2 data, NASADEM also relied on Ice, Cloud, and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) ground control points of its lidar shots to improve surface elevation measurements that led to improved geolocation accuracy. Other reprocessing improvements include the conversion to geoid reference and the use of GDEMs and Advanced Land Observing Satellite Panchromatic Remote-sensing instrument for Stereo Mapping (PRISM) AW3D30 DEM, and interpolation for void filling.NASADEM are distributed in 1 degree latitude by 1 degree longitude tiles and consist of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth's total landmass. NASADEM_HGT data product layers include DEM, number of scenes (NUM), and an updated SRTM water body dataset (water mask). The NUM layer indicates the number of scenes that were processed for each pixel and the source of the data. A low-resolution browse image showing elevation is also available for each NASADEM_HGT granule.The global 1 arc second NASADEM product is also available in NetCDF4 format as the NASADEM_NC dataset with the source of each elevation pixel in the corresponding NASADEM_NUMNC product.

Layers include: Ensemble Digital Terrain Model (EDTM) in 250-m resolution. Unit is in metre(m) and precision is in decimetre (dm). Maps are downscaled from 30-m resolution to 250-m in order to fit the size limit. We provide 30-m EDTM and its standard deviation as links:

• 30-m EDTM

https://s3.eu-central-1.wasabisys.com/openlandmap/dtm/dtm.bareearth_ensemble_p10_30m_s_2018_go_epsg4326_v20230221.tif

• Standard deviation

https://s3.eu-central-1.wasabisys.com/openlandmap/dtm/dtm.bareearth_ensemble_std_30m_s_2018_go_epsg4326_v20230221.tif

Derived using ALOS AW3D, GLO-30, MERITDEM, and national DTMs. We derived a lower 10% quantile from all maps. In order to create bare earth data, we used canopy height (canopy height > 2m) and standard deviation (sd > 6m) to mask building and forest in AW3D and GLO-30. Practical processing is written here in Python.

To access and visualize maps use: OpenLandMap.org

If you discover a bug, artifact or inconsistency, or if you have a question please use some of the following channels:

• Technical issues and questions about the code: https://gitlab.com/openlandmap/global-layers/-/issues
• General questions and comments: https://disqus.com/home/forums/landgis/

All files internally compressed using "COMPRESS=DEFLATE" creation option in GDAL in Cloud Optimised GeoTiff (COG). File naming convention:

• dtm.bareearth = variable: digital terrain model (m), bare earth
• ensemble = determination method: ensemble of mutli-source dsm and dtm
• p10/std = aggregation/statistics method: 10th percentile / standard deviation
• 250m = spatial resolution / block support: 250 m,
• s = vertical reference: at surface,
• go = bounding box: global land without Antarctica
• epsg.4326 = ESPG code: epsg.4326
• v20230221 = version code: creation date 20230221

ALOS World 3D - 30m (AW3D30)는 가로 해상도가 약 30m (1아르크초 메시)인 전 세계 디지털 표면 모델 (DSM) 데이터 세트입니다. 이 데이터 세트는 세계 3D 지형 데이터의 DSM 데이터 세트(5m 메시 버전)를 기반으로 합니다. 자세한 내용은 데이터 세트 문서를 참고하세요. 처리된 이 데이터 세트는 버전 3.1, 4.0, 4.1의 데이터를 결합합니다. 버전 4.1 (2024년 4월): 이 주요 업데이트에서는 전 세계 지역 (남극과 일본 제외)을 다루는 19,051개의 타일을 출시했습니다. 이 버전은 공백 채우기를 위한 새로운 보조 데이터를 통합하고 버전 3.1 및 3.2에서 발견된 부분적 이상치를 수정하고 공백을 다시 채웁니다. v4.1의 특정 카드 업데이트의 경우 지도 카드에서 v4.1 필터를 사용하거나 최신 형식 설명을 참고하세요. 버전 4.0 (2023년 4월): 이 업데이트에서는 1,886개의 타일을 출시하여 저위도 및 중위도 지역과 위도 60도 남쪽의 지역을 개선했습니다. 주요 변경사항은 다음과 같습니다. 1. 공백 채우기를 위한 새로운 보조 데이터 2. 부분적인 이상치를 수정하고 공백을 다시 채웁니다 (타일 2개). 3. 위도 60도 남쪽 지역의 해안선을 업데이트했습니다 (44개 타일). 4. 카스피 해 수역 마스킹을 사용 중지하고 고도 데이터(54개 타일)로 보완했습니다. 5. 남미의 새로운 부분적 이상 영역(1,786개 타일)을 추출하여 수정했습니다. 6. v4.0의 자세한 카드 정보는 지도 카드에서 v4.0 필터를 사용하거나 형식 설명을 참고하세요. 2021년 1월에 출시된 버전 3.2는 고위도 지역의 형식, 보조 데이터, 처리 방법을 재고하여 만든 개선된 버전입니다. 고위도 지역에서는 위도 영역별로 다른 픽셀 간격이 채택되었습니다. 보조 데이터 세트 중 하나인 해안선 데이터가 변경되고 새로운 보조 데이터가 사용되었습니다. 또한 일본의 소스 데이터로 AW3D 버전 3도 사용되었습니다. 또한 프로세스에서 이상 값을 감지하는 방법이 개선되었습니다. 참고: 경사 계산의 권장 방법은 코드 예시를 참고하세요. Earth Engine의 대부분의 DEM과 달리 이 DEM은 소스 파일의 해상도가 여러 개여서 단일 애셋으로 모자이크 처리할 수 없으므로 이미지 모음입니다. 따라서 경사 계산에는 재프로젝션이 필요합니다. AW3D DSM 고도는 광학 이미지의 스테레오 쌍을 사용하는 이미지 일치 프로세스로 계산됩니다. 처리 중에 구름, 눈, 얼음이 자동으로 식별되고 마스크 정보가 적용됩니다. 그러나 일치하지 않는 지점이 특히 구름, 눈, 얼음 지역 주변 (또는 가장자리)에 남아 최종 DSM에 일부 고도 오류가 발생하는 경우가 있습니다.

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Digital Elevation Model (DEM) version 1 (NASADEM_SSP) dataset, which provides global Shuttle Radar Topography Mission (SRTM) sub-swath elevation data at 1 arc second spacing.NASADEM data products were derived from original telemetry data from the Shuttle Radar Topography Mission (SRTM), a collaboration between NASA and the National Geospatial-Intelligence Agency (NGA), as well as participation from the German and Italian space agencies. SRTM's primary focus was to generate a near-global DEM of the Earth using radar interferometry. It was a primary component of the payload on space shuttle Endeavour during its STS-99 mission, which was launched on February 11, 2000, and flew for 11 days. In addition to Terra Advanced Spaceborne Thermal and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 2 data, NASADEM also relied on Ice, Cloud, and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) ground control points of its lidar shots to improve surface elevation measurements that led to improved geolocation accuracy. Other reprocessing improvements include the conversion to geoid reference and the use of GDEMs and Advanced Land Observing Satellite Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) AW3D30 DEM, and interpolation for void filling.NASADEM are distributed in 1 degree latitude by 1 degree longitude tiles and consist of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth's total landmass. NASADEM_SSP data product layers include radar total correlation, radar volumetric correlation, radar individual images, radar incidence angle (relative to ellipsoid), and radar incidence angle (local). A low-resolution browse image showing sub-swath elevation is also available for each NASADEM_SSP granule.

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Digital Elevation Model (DEM) version 1 (NASADEM_SIM) dataset, which provides global Shuttle Radar Topography Mission (SRTM) image mosaic data at 1 arc second spacing.NASADEM data products were derived from original telemetry data from the Shuttle Radar Topography Mission (SRTM), a collaboration between NASA and the National Geospatial-Intelligence Agency (NGA), as well as participation from the German and Italian space agencies. SRTM's primary focus was to generate a near-global DEM of the Earth using radar interferometry. It was a primary component of the payload on space shuttle Endeavour during its STS-99 mission, which was launched on February 11, 2000, and flew for 11 days. In addition to Terra Advanced Spaceborne Thermal and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 2 data, NASADEM also relied on Ice, Cloud, and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) ground control points of its lidar shots to improve surface elevation measurements that led to improved geolocation accuracy. Other reprocessing improvements include the conversion to geoid reference and the use of GDEMs and Advanced Land Observing Satellite Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) AW3D30 DEM, and interpolation for void filling.NASADEM are distributed in 1 degree latitude by 1 degree longitude tiles and consist of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth's total landmass. NASADEM_SIM data product layers include radar combined images and a NUM file associated with combined images. A low-resolution browse image showing the SRTM image mosaic elevation is also available for each NASADEM_SIM granule.