AI Maps 13 Million Buildings in One of the World’s Most Remote Regions

Authors: Tao Ye Hongyu Shan Jidong Wu Qiang Zhou Mingfu Ma Wenzhi Zhao Ru Ya Yuan Gao Lizheng Wu Authors: Tao Ye Hongyu Shan Jidong Wu Qiang Zhou Mingfu Ma Wenzhi Zhao Ru Ya Yuan Gao Lizheng Wu Tao Ye Hongyu Shan Jidong Wu Qiang Zhou Mingfu Ma Wenzhi Zhao Ru Ya Yuan Gao Lizheng Wu Abstract Large-scale high-precision building distribution data is important fundation for regional urban planning and resource allocation and disaster risk research. The Qinghai-Tibetan Plateau is the third pole of the world. Although understanding local human–environment interactions in the Qinghai-Tibetan Plateau is critically important, this has been hindered by a lack of high-resolution building footprint data due to the vastness and remoteness of the area. In this study, we generated the first vectorized building rooftop prints of the Qinghai-Tibetan Plateau and its surrounding areas by using high-resolution Google imagery and the building contour extraction algorithm of the AI Earth platform. Our results include 13.09 million buildings covering 6092.7 km2, validated with a total of 250 × 1 km2 test samples. The data had an overall accuracy of 87%, a recall of 91.9%, and an F1 score of 64.8%, thus providing an advanced description of the building distribution of the study area as compared to CBRA. Our work has immense potential in facilitating exposure assessment for studies on disaster risk in this area. Background & Summary The advent of the digital era has increased the demand for reliable data on building distribution and attributes1,2,3. Building distribution data provide important spatial information of not only buildings but also population and physical assets4, serving as a good proxy for human activity. In recent decades, building distribution data have been widely used in monitoring urban and rural development5,6, understanding the impacts of urbanization on food security, biodiversity, climate change, and public well-being and health7,8, formulating regional development strategies, and protecting urban and rural ecosystems9,10,11. 1 2 3 4 5 6 7 8 9 10 11 The advancement of satellite-based and airborne imagery, together with recent progress in machine learning and deep learning algorithms, has boosted the availability of building distribution data12,13,14. Building distribution data have been provided in raster format as a part of land use/cover data. The most up-to-date release includes three 10-m global land use/cover products based on Sentinel satellites, namely Google’s Dynamic World (DW)15, Esri’s 2020 Land Cover16, and World Cover 2020 (WC) of the European Space Agency (ESA)17. Besides spatial distribution information, researchers are also trying to attach attribute information to building pixels, such as building height14. For example, He et al.7 used multi-source remote sensing data fusion to construct the world’s first 30-m-resolution urban three-dimensional spatial and temporal sprawl dataset covering the period from 1990 to 2010. Despite the continuous improvement of spatial resolution, raster-based building distribution data still cannot describe spatial objects18, and increasing resolution greatly increases storage and computing costs12. 12 13 14 15 16 17 14 et al 7 18 12 Building distribution data in vector format, also known as vectorized building rooftop or building footprints, are the outline data of a building projected onto the ground in an overhead view19,20, which provide information such as the geographic location, spatial extent of the boundaries, and footprint of a single building. Public service providers (e.g., Google Earth and OpenStreetMap) provide open-access vectorized building rooftop data with wide coverage, fast updates, and low cost21,22,23. In 2022, Microsoft Corporation used deep neural network–based semantic segmentation to extract the outlines of 777 million buildings, some of which containing building height attributes, based on Bing Maps (including Maxar and Airbus imagery) from 2014 to 2021 for every continent outside of China. On May 30, 2023, Google released a dataset of 1.8 billion building outlines extracted from 0.5-m high-resolution satellite imagery, covering an area of 58 million km2. The low redundancy and compact structure of vector data represented by vertices and paths provide higher geographic accuracy independent of mesh size, and the introduction of topological rules further improves the integrity of vector data13. 19 20 21 22 23 13 Due to the increase in imagery resolution and the decrease in data acquisition costs, together with recent progress in extraction algorithms, the resolution and coverage of building distribution data are continuously improving24. The viability of very-high-resolution (VHR) images has enabled the extraction of building footprints by the application of traditional hand-crafted feature-based methods25 or deep learning–based methods13. As the former approach faces the challenge of diversity of building appearances and sizes, and complex rules of thumb and threshold settings, it is limited when applied to large-scale high-resolution remote sensing images26. Deep learning–based methods (e.g., convolutional neural networks) have shown effective and superior performance in automatically learning high-level and discriminative features in building scene segmentation. Sun et al.27 proposed a fusion strategy based on parallel support vector machines to fully utilize deep features extracted from multi-scale convolutional neural network structures at different scales, with superior performance in extracting complex buildings in urban areas. Nevertheless, when segmenting buildings, the accuracy of the model is more likely to be constrained by the quality of the training samples, making extrapolation difficult. Insufficient use of high-level semantics and omission of low-level details in deep models, resulting in edge-blurring and small-building omissions, also hinder the application of deep learning in building footprints extraction. 24 25 13 26 et al 27 The Qinghai-Tibetan Plateau region is the world’s most elevated area, with an average elevation of >4000 meters above sea level, and covers an area of 2.5 million km2 28. More than 10 million people inhabit the region despite its extreme climate, cold and long winters, large annual and diurnal temperature differences, and poor indoor thermal environments. Although this region is the largest ecological barrier in China29, human activity considerably impacted its vulnerable eco-environment30. This region is also extremely disaster-prone, with earthquakes, landslides, mudslides, glacial lake outburst floods, and snow disasters leading to casualty and property losses31,32,33. In response, accurate building distribution data are critical for modelling human activity distribution for coupled human–environment study34,35, as well as exposure and risk analysis for natural disasters36,37. In addition, this region has long sunshine hours, abundant solar energy resources, and sufficient solar energy collection surfaces such as rooftops and open spaces38,39. High-resolution rural building distribution data could provide a reliable database for evaluating photovoltaic potential and efficiently improving the living standards of those living in rural areas40,41. 28 29 30 31 32 33 34 35 36 37 38 39 40 41 As an underdeveloped region, the Qinghai-Tibetan Plateau and its neighboring areas still do not have a complete set of high-precision vectorized building rooftop data, owing to their vast area, sparse building distribution, remote location, and resource constraints. The most ready-to-use data are those provided at the national scale of China, which include the 2.5-m gridded China Building Rooftop Area data (CBRA, Liu et al., 2023b) and China’s first national land cover map with 1-m resolution (SinoLC) that includes building categories42. These raster data are unable to characterize spatial objects and require large storage resources. The vectorized rooftop area data for 90 major cities in China released by Zhang et al.13 partly filled this gap; however, only 14 cities in the Qinghai-Tibetan Plateau were included in this dataset, and vectorized building rooftop data are still absent for an area of 2 million km2. et al 42 et al 13 Therefore, this study aims to generate vectorized building rooftop prints of the Qinghai-Tibetan Plateau and its neighboring regions by incorporating high-resolution satellite imagery and deep learning algorithm. Our dataset was validated using test samples comprising 250 × 1 km2 grids across various sub-regions, resulting in an overall accuracy of 91.92% and an F1 score of 64.81%. Methods Framework In this study, we utilized building extraction algorithms from the AI Earth platform to generate a vectorized building rooftop dataset for the Qinghai-Tibetan Plateau and its neighboring region in China (Fig. 1). The principal components of our framework included: (1) satellite data and auxiliary data preparation and preprocessing; (2) vectorized building rooftop extraction using AI Earth platform; (3) validation using manually vectorized rooftop data. 1 The framework for building rooftop extraction and validation. Study area This study mainly focused on the Qinghai-Tibetan Plateau and its neighboring regions in southwestern China under the general framework of the second Tibetan Plateau Scientific Expedition and Research Program43; geographically, it includes the Tibetan Autonomous Region, Qinghai Provinces, western Yunnan Province, western Sichuan Province, southwestern Gansu Province, and southern Xinjiang Autonomous Region. The average elevation of the study area is 4000-m above sea level. The distribution of population and buildings in the study area is highly influenced by elevation and climate (Fig. 2), mainly concentrating east of the line from Jilong County in Tibet to Qilian County in Qinghai44; in the east, they distribute densely in the plain areas on the eastern edge of the region, including the river valleys in Yunnan Province, western Sichuan Province, and the Xining-Lanzhou Yellow River Basin. In the plateau surface west of the line, population and buildings are mostly distributed with limited agro-pastoral areas along the major river valleys, and along road traffic corridors. 43 2 44 Study area (population data are from LandScan; DEM is from Resource and Environment Science and Data Centre). Satellite imagery Open-access high-resolution satellite image data were obtained from Rivermap Co. (http://www.rivermap.cn/index.html), which were obtained from Google Earth’s integration of satellite imagery and aerial data. Among them, the satellite imagery mainly comes from DigitalGlobe’s QuickBird and WorldView commercial satellites, and the aerial photography is sourced from BlueSky in the UK and Sanbornin the US45. For each location, there were collections of multiple imageries with resolutions of up to 0.15 m in localized areas. Such data integration has been widely used for object recognition in complex scenes46,47,48,49 and has the potential for large-scale high-resolution mapping of object types50. http://www.rivermap.cn/index.html 45 46 47 48 49 50 The total area of our study area is 3.06 million km2, and the estimated size of the satellite image data is 29.4 TB, with a spatial resolution of 0.6 m. Considering these scales, 0.175° × 0.175° fishnets were created for our study area to enable smaller-size packages for download, with a total of 10,033 fishnets used to cover the whole study area. The actual number of fishnets downloaded was smaller at 5921 for two reasons. First, as a large part of the study area comprises non-human residential areas where buildings do not exist, we arbitrarily excluded fishnets without any built-up area pixels from the ESA World Cover product. Second, cities/prefectures whose vectorized rooftop data (i.e., Lhasa, Shannan, Kunming, Xining, Haidong, Zhangye, Baiyin, Lanzhou, Chengdu, Dali, Lijiang, Kunming, Zhaotong, and Yuxi) have been retrieved in the vectorized rooftop area data for 90 cities in China13 were also excluded. The images were downloaded during September 2022 and January 2023, with a resolution of 0.6 m, a single frame size of ca. 3 GB, and a total size of 2.72 TB. Images downloaded were mainly taken from 2019 to 2021, but images from some remote areas may have been taken as early as 2001 (Fig. 3). 13 3 Fishnets for image download and image shooting time. Auxiliary data Our auxiliary data included high-resolution land cover maps, digital elevation model (DEM), normalized difference vegetation index (NDVI), and population distribution data for subsequent cluster analysis for the purpose of sampling (Table 1). 1 For land cover and built-up area, ESA’s World Cover product from Zanaga et al.17 was obtained from Zenodo (https://zenodo.org/records/5571936). The product was generated based on Sentinel 1 and Sentinel 2 satellite imagery for the entire year of 2020 and a sample of 141,000 unique locations distributed around the world, trained with the random forest algorithm, to represent global land cover in 2020; it has an advantage in representing fine-scale landscape elements (e.g., built-up areas and complex agricultural landscapes), as it considers a relatively small minimum mapping unit51. The “built-up” category in the dataset refers to land covered by buildings, roads, and other man-made structures (e.g., railroads) but excluding urban green spaces (e.g., parks and sports facilities), landfill deposits, and mining sites17. et al 17 https://zenodo.org/records/5571936 51 17 The 1-km DEM data and NDVI data were obtained from the Resource and Environment Science and Data Centre, Institute of Geoscience and Resources, Chinese Academy of Sciences (https://www.resdc.cn/Default.aspx). The DEM data are resampled from the latest SRTM V4.1 data (https://www.resdc.cn/data.aspx?DATAID=123), and the NDVI data are mosaiced based on SPOT/VEGETATION PROBA-V 1-km products (http://www.vito-eodata.be). We chose the NDVI data of 2021 to represent vegetation on the Qinghai-Tibetan Plateau (https://www.resdc.cn/DOI/DOI.aspx?DOIID=49). Population density data were obtained from the LandScan database (https://landscan.ornl.gov/) for global vital statistics analysis developed by the U.S. Department of Energy’s Oak Ridge National Laboratory and provided by East View Cartographic (https://geospatial.com/); these data are generated by combining geospatial science, remote sensing technology, and machine learning algorithms, representing one of the most accurate and reliable global population dynamic statistical analysis databases based on geographic location, with superior resolution at 1 km52. We used the population distribution in 2021 for subsequent cluster analysis. https://www.resdc.cn/Default.aspx https://www.resdc.cn/data.aspx?DATAID=123 http://www.vito-eodata.be https://www.resdc.cn/DOI/DOI.aspx?DOIID=49 https://landscan.ornl.gov/ https://geospatial.com/ 52 Data pre-processing The distribution of population and buildings is scattered for most of our study area, with over 99.5% of the study area categorized as non-built-up areas according to the ESA’s World Cover product17. To expediate our extraction, masks of potential building distribution area were first generated for each 0.175° × 0.175° fishnet before extraction. Based on the “Built-up” category in the World Cover data, a 1-km buffer zone surrounding each built-up area pixel was generated as the potential building distribution area. After testing several buffer zone widths, we found that a width of 1 km could accommodate 96% of the building pixels reported in the CBRA products of 2020. The mask enabled us to exclude 86% of the total area of the downloaded imageries, consequently saving substantial computational time. We analyzed the buffer using an overlay with the generated fishnets to exclude nets that did not contain buildings. The images were then cropped again with buffers, and then the building extraction algorithm was applied to the cropped images. 17 Vectorized building rooftop extraction The vectorized building rooftop extraction algorithm used in this study is from the AliCloud AI Earth platform (https://engine-aiearth.aliyun.com/#/), which combines a deep learning–based segmentation method with a watershed-based segmentation method to construct a building instance segmentation framework - double decoder for watershed segmentation. This algorithm adds a boundary segmentation task to the semantic segmentation task, and uses the watershed algorithm to preprocess the prediction results of the two tasks during prediction, obtaining the final building extraction result. The PointRend neural network proposed by Kirillov et al.53 is used first53, which treats image segmentation as a rendering problem and employs an iterative segmentation algorithm that selectively samples non-uniform points for accurate segmentation, as more stable and accurate seed points learned by the neural network can provide finely tuned semantic segmentation models for key structures and features of the building. Subsequently, a flexible watershed segmentation is used for post-processing54,55, which is able to adapt to objects with different morphologies and features. The algorithm achieves a counting accuracy of >90% and an area estimation accuracy of >85% in validation testing based on manual vectorized samples in different regions of China, winning second place in the all-weather SAR image building segmentation competition SpaceNet6. Compared to Mask Region-CNN, the algorithm improves the mean average precision by 11 percentage points56. https://engine-aiearth.aliyun.com/#/ et al 53 53 54 55 56 Data Records The vectorized building rooftop extraction algorithm used in this study can be called on the AI Earth platform (https://engine-aiearth.aliyun.com/#/). Our dataset is available from the National Tibetan Plateau Data Centre, which can be accessed at https://doi.org/10.11888/RemoteSen.tpdc.30117057. All data are obtained using the GCS_ WGS_ 1984 coordinate system and packaged into.rar files (Table 2). The generated AI-based building contour data (Fig. 4) is arranged on province level according to their name, including Gansu, Guizhou, Qinghai, Sichuan, Xinjiang, Xizang, and Yunnan. In addition, image data of the corresponding 250-km2 grid and manually drawn verification data from original sources were also uploaded in ‘image_1km.rar’ and ‘test_1km.rar’. The year of image acquisition in Fig. 3 is in ‘image_time.rar’. https://engine-aiearth.aliyun.com/#/ https://doi.org/10.11888/RemoteSen.tpdc.301170 57 2 4 3 Extraction results. Technical Validation Validation data preparation based on stratified sampling Manually building rooftop vectorization was conducted to derive “ground-truth” building rooftop data for validation purposes. Due to the vast area of our study area, as well as substantial regional differences in terms of elevation, landform, vegetation type, and building type, we used a stratified sampling approach instead of random sampling to obtain a balanced sample in terms of different sub-regions. We performed K-means clustering58 on the 5921 fishnets based on five indicators: built-up area, mean NDVI, population density, mean elevation, and standard deviation of elevation. K-means clustering is a clustering algorithm based on Euclidean distance, in which the closer the distance between the characteristics of two targets, the greater the similarity. After standardizing the data by subtracting the mean and dividing by the standard deviation, the elbow method was used to select the most suitable number of categories59. During the process, when the number of categories was increased to five, the rate of decrease of the sum of squared errors declined rapidly. Therefore, we clustered the 5921 fishnets into five categories for subsequent analyses (Table 3, Fig. 5). 58 59 3 5 Geographical zoning map and fishnets for creating validation dataset. Cluster I (plateau surface & low building density zone) covers a large area on the plateau surface of the Qinghai-Tibetan Plateau—with the widest area and the flattest terrain—and is characterized by high elevation, low population, low vegetation cover, and low built-up area. Fishnets in Cluster II (high altitude & mid-to-low building density zone) are mainly located at the border regions of Qinghai, Sichuan, and Tibet, and are mostly covered with alpine meadows and shrubs, and mainly the headwaters of large rivers in China. However, the climate conditions of Cluster II are relatively harsh, resulting in a relatively sparse population and buildings here. Fishnets in Cluster III (largest terrain relief & mid building density zone) have the greatest variability in elevation, located mainly in the topographic transition zone around the plateau. Cluster IV (mid-low altitude & mid-high building density zone) mainly includes Gansu and Yunnan provinces in the eastern part of the Qinghai-Tibetan Plateau, with relatively low elevation, lush vegetation, and dense population and buildings. Cluster V (low altitude & high building density zone) has the smallest number of fishnets but the most urban area, the lowest average elevation, and the highest population and building densities. A total of 250 fishnets were then selected based on the division of clusters; within each fishnet, a 1-km2 grid was used to prepare ground truth data for accuracy validation, which yielded a sampling rate of 4.22% (250/5921 fishnets) or 0.093% (250 km2/267904 km2 buffer mask). The number of the sampling fishnets selected for each cluster is proportionate to its total size. Within each cluster, we give priority to fishnets with large built-up area in ESA’s World Cover product. During this process, we also attempted to avoid selecting neighboring fishnets so that the sample could guarantee a better spatial coverage. The final distribution of selected fishnets is shown in Fig. 5. Each sampled fishnet was then divided into 1-km2 grids, and the grid with the largest built-up area according to ESA’s World Cover product was selected for manual building rooftop vectorization. Finally, we obtained a total of 149,035 manually outlined buildings with a total area of 24.65 km2. 5 Validation result We used a quantitative approach12 to validate our extraction results, referring to a multi-criteria hierarchical evaluation system for evaluating buildings extracted based on remote sensing (Zeng et al.60). Based on the manually vectorized building rooftop data, the match rate metrics (Table 4) of the 250 × 1 km2 grids, including overall accuracy (OA), precision, recall, and F1 score for precision evaluation61, were computed based on the confusion matrix62. 12 et al 60 4 61 62 The OA of our result is 87%, indicating that our dataset has high credibility in extracting buildings and excluding backgrounds (Table 5). However, a precision score of 50.1% indicates that approximately half of building rooftop areas extracted are incorrect, which is mainly due to false prediction of building spacing in areas of high building density (e.g., in high-density built-up areas where the spacing between buildings is small). The recall of our results is approximately 92%, which means that manually vectorized building roofs can be mostly extracted by the algorithm. Our results were slightly better than CBRA12 and the vectorized rooftop area data for 90 cities in China13. Compared with our result, based on our validation dataset, CBRA has a comparable OA but relatively small precision, recall, and F1 score. The vectorized rooftop area data for 90 cities in China were reported to have an OA of 83.4% and a recall of 79.0%12, which may be due to the image semantic segmentation model it used lacking a specialized extraction module. 5 12 13 12 The performance of our extraction differed by fishnet clusters, suggesting the challenges of distinguishing rooftop from environmental background, and proving the reasoning of adopting stratified sampling in validation (Table 5). There are pronounced differences in the OA and recall between clusters. In general, OA decreases but recall decrease with the decrease of average altitude and the increase of built-up area. However, the difference in precision between clusters is relatively small, indicating that the proportion of real buildings in the extracted results of each cluster is relatively close. 5 To further understand the challenges of extraction, the visualization results of elements in the confusion matrix (TP, TN, FP, and FN) for different clusters are shown in Figs. 6–10; each sub-image corresponds to a sampled 1 km2 grid, with the original image on the left, the extracted results from this study in the middle, and the results of the CBRA product on the right. Elements in the confusion matrix—TP, TN, FP, and FN—correspond to correct building, correct background, misidentified building, and unidentified building in the legend, respectively. Validation metrices are also supplied below their corresponding results. 6 10 Accuracy evaluation for Cluster I (a,d: raw image; b,e: our results; c,f: CBRA). a,d b,e c,f Accuracy evaluation for Cluster II (a,d: raw image; b,e: our results; c,f: CBRA). a,d b,e c,f Accuracy evaluation for Cluster III (a,d: raw image; b,e: our results; c,f: CBRA). a,d b,e c,f Accuracy evaluation for Cluster IV (a,d: raw image; b,e: our results; c,f: CBRA). a,d b,e c,f Accuracy evaluation for Cluster V (a,d: raw image; b,e: our results; c,f: CBRA). a,d b,e c,f Cluster I mainly covers the plateau surface area of Qinghai-Tibetan Plateau, which is the largest and flattest among the five clusters, with sparse vegetation and widespread bare land. The buildings in this cluster mainly exhibit sparse distribution on a large scale and dense distribution locally (Fig. 6a); it has the highest OA (94.6%) and precision (52.7%) among the five clusters, but the lowest recall (78.8%) and F1 score (60.6%). The low recall indicates that there is still a considerable portion of buildings in the cluster that have not been extracted by the algorithm. However, the high OA is maintained in this cluster due to the small area of buildings relative to the large area of background. The roofs in densely populated local places are mainly white and blue, including some large industrial plants (Fig. 6a). Their difference from bare land gives the relevant 1-km grids high extraction accuracy (approximately 100% OA and recall). The houses in sparsely distributed areas are mostly single-story residential buildings, with gray-black roofs that are less distinguishable from the surrounding bare land, resulting in FN (e.g., the scattered buildings in the bottom-right corner of Fig. 6d). In this cluster, CBRA has a comparable OA but relatively small recall, precision, and F1 score according to our validation dataset; its high OA is also due to its correct recognition of large areas of background. 6a 6a 6d Cluster II is mainly located in the high-altitude area in eastern Qinghai-Tibetan Plateau; its population and built-up area are slightly larger than those of cluster I, with a higher number of settlements, but still the general distribution of buildings is relatively sparse. This cluster has a relatively higher OA (87.9%) and a relatively lower precision (48.6%) among the five clusters (Table 5); it has many red-tiled and blue-roofed masonry buildings, making it easier to distinguish the buildings from the brown bare ground. This results in a remarkable improvement in recall (87.5%), and the issue of missing building blocks (FN) is also relieved, as compared to cluster I. However, as the number of buildings increases, the amount of FP also begins to rise. The CBRA product has a good recall (49.4%) in this cluster but experiences difficulty in extracting individual buildings (Fig. 7). 5 7 Cluster III is a transitional area from high altitude mountainous plateaus to low altitude hilly plains. As altitude decreases, population density and built-up area further increase. It has the largest terrain relief among the five clusters. The buildings in this cluster are mainly concentrated in low mountain and valley areas and are distributed along rivers and contour lines (Fig. 8a). At the same time, a certain number of high-rise residential buildings appear in the cluster, whose rooftops are mostly gray with obvious edges, and a relatively large distance between them (Fig. 8d). Therefore, the algorithm is more precise when extracting their rooftop contours compared to other buildings, yielding a high recall for this cluster (91.8%). However, shadows caused by high-rise buildings and mountains resulted in increased FNs, and the background pixels at the shadow edges were misidentified by the algorithm, leading to some FPs. CBRA also has better validation metrics in this cluster compared to clusters I and II, as it can identify the buildings in the main densely populated areas. However, it also is negatively impacted by building shadows (FP, bottom of Fig. 8a). 8a 8d 8a Cluster IV is mainly located in valley and small-plain areas with lower elevations and flatter terrain around the plateau. It has a larger average built-up area, more population, and more large-scale individual buildings than clusters I–III, and the arrangement of buildings in this cluster is more orderly (Fig. 9a,d). Based on this context, the OA (75.7%) of this cluster is smaller, whereas the precision (52.5%), recall (93.8%), and F1 score (66.7%) are all higher to varying degrees compared to clusters I–III. For buildings with clear boundaries and large rooftop areas, our results maintain their integrity and sharp edges. Our results well capture contiguous building areas, and the extraction of external envelope lines is very successful. However, our method struggled to distinguish densely connected buildings, such as apartment buildings, whose building spacing is often small. This difficulty led to blob-like segmentation results. For example, in the densely populated area shown in Fig. 9d, the open spaces between buildings have similar spectral features to the buildings, and the distance between adjacent buildings is small. Although this phenomenon also exists in CBRA, relatively speaking, our results have a lower proportion of FP by identifying some small roads in dense building areas (Fig. 9d). At the same time, both products did not mistakenly identify the main road as a building, indicating that they can effectively distinguish the characteristic differences between roads and buildings63. 9a,d 9d 9d 63 Cluster V mainly comprises densely populated urban areas with low and flat terrain around the plateau. Its OA (76.8%) is the lowest among all clusters, mainly due to the increase in FP and the decrease in TN (Fig. 10e). However, this cluster has the highest recall (96.3%) and F1 score (67.5%) among the five clusters. The high recall indicates that most of the buildings in the cluster can be extracted by the algorithm (Fig. 10b,e), which may be because it has been well trained by the AI Earth platform based on urban areas with high building density. At the same time, the urbanization level of this cluster is higher, and there are fewer dense and small scattered buildings that are difficult to distinguish from the background, which slightly improve precision (0.4%) and F1 score (1.4%) compared with cluster IV. CBRA is similar to our results, but there is also a problem of FN in areas of high building density. For the special case of small buildings at the top of a large-area building (Fig. 10a,b), our results consider the bottom building as the background value, whereas CBRA can fully extract the entire building. 10e 10b,e 10a,b Usage Notes The high-resolution building rooftop prints extracted based on AI Earth building rooftop extraction algorithm in the Qinghai-Tibetan Plateau and its neighboring region is suitable for research on large-scale building distribution, spatial structure, urbanization process, and human activity intensity. In a complex and ecologically sensitive region like the Qinghai-Tibetan Plateau, such building data can provide important support for urban and rural planning, infrastructure assessment, and research on human land relationships. In addition, it can provide building exposure data foundation for disaster risk assessment and ecological protection planning. Our dataset also offers original data of 250 × 1 km2 manually vectorized building rooftop data. Although the coverage is small as compared to the area of the study area, it is very suitable as benchmark data to evaluate the accuracy and stability of automated building extraction algorithms due to its high accuracy and controllable errors. In addition, it can also be used for more detailed research tasks such as building density analysis, micro scale urban structure research, and architectural style recognition. If further combined with ground measurements, it can serve as an important data foundation for architectural research in high-altitude special areas. Our method to some extent balances the convenience of data acquisition and the efficiency of automated processing, but there are still some limitations that cannot be ignored from multiple perspectives. Firstly, from the perspective of data sources, although the remote sensing images provided by Google Earth have high resolution, they enable us to obtain data covering the entire research area at a lower cost. However, due to the large research area, these images are not uniform, and there are differences in clarity, lighting conditions, and shooting angles among images obtained from different regions and at different times. Some images of fishnet can be traced back to 2001, with low resolution, resulting in less detailed spatial information and greatly reducing extraction accuracy. In the future, this problem can be solved by replacing these images with newer ones. Secondly, from an algorithmic perspective, the building extraction algorithm of Alibaba Cloud AI Earth platform performs well overall in the Qinghai-Tibet Plateau scene. However, due to the influence of easily confused backgrounds, there are still adhesion phenomena in densely built areas, especially in scenes with Tibetan style buildings or small settlements on the plateau that are dense but strongly obscured, and the accuracy of building contour extraction will decrease. In the future, deep-learning-based edge detection modules can be further added to the extraction algorithm to enhance the extraction of architectural form features. Lastly, as for the extraction results, due to the use of masks from ESA’s 10 m land cover products, there may be a small number of scattered building areas with built-up areas less than 100m2 that are missing. In addition, historical images can be used to generate a dynamic distribution of buildings over many years in the future to provide more detailed building information. Code availability No custom code was used to generate or process the first vectorized building rooftop prints of the Qinghai-Tibetan Plateau and its neighboring regions. The website of AI earth platform is https://engine-aiearth.aliyun.com/. The software used in the technical validation of our dataset was ArcMap version 10.8. https://engine-aiearth.aliyun.com/ References Acuto, M., Parnell, S. & Seto, K. C. Building a global urban science. Nat Sustain 1, 2–4 (2018). Biljecki, F., Arroyo Ohori, K., Ledoux, H., Peters, R. & Stoter, J. Population Estimation Using a 3D City Model: A Multi-Scale Country-Wide Study in the Netherlands. PLoS ONE 11, e0156808 (2016). Hu, Q., Zhen, L., Mao, Y., Zhou, X. & Zhou, G. Automated building extraction using satellite remote sensing imagery. Automation in Construction 123, 103509 (2021). 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Journal of Cleaner Production 296, 126556 (2021). Assouline, D., Mohajeri, N. & Scartezzini, J.-L. Large-scale rooftop solar photovoltaic technical potential estimation using Random Forests. Applied Energy 217, 189–211 (2018). Shepero, M., Munkhammar, J., Widén, J., Bishop, J. D. K. & Boström, T. Modeling of photovoltaic power generation and electric vehicles charging on city-scale: A review. Renewable and Sustainable Energy Reviews 89, 61–71 (2018). Liu, Z., Tang, H., Feng, L. & Lyu, S. China Building Rooftop Area: the first multi-annual (2016–2021) and high-resolution (2.5 m) building rooftop area dataset in China derived with super-resolution segmentation from Sentinel-2 imagery. Earth Syst. Sci. Data 15, 3547–3572 (2023). Zhang, Z. et al. Vectorized rooftop area data for 90 cities in China. Sci Data 9, 66 (2022). Wu, W.-B. et al. A first Chinese building height estimate at 10 m resolution (CNBH-10 m) using multi-source earth observations and machine learning. Remote Sens. Environ. 291, 113578 (2023). Brown, C. F. et al. Dynamic World, Near real-time global 10 m land use land cover mapping. Sci Data 9, 251 (2022). Karra, K. et al. Global land use/land cover with Sentinel 2 and deep learning. in 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS 4704–4707. https://doi.org/10.1109/IGARSS47720.2021.9553499 (IEEE, Brussels, Belgium, 2021). Zanaga, D. et al. ESA WorldCover 10 m 2020 v100. Zenodo https://doi.org/10.5281/zenodo.5571936 (2021). Jakubowski, M., Li, W., Guo, Q. & Kelly, M. Delineating Individual Trees from Lidar Data: A Comparison of Vector- and Raster-based Segmentation Approaches. Remote Sensing 5, 4163–4186 (2013). Guo, H., Shi, Q., Marinoni, A., Du, B. & Zhang, L. Deep building footprint update network: A semi-supervised method for updating existing building footprint from bi-temporal remote sensing images. Remote Sens. Environ. 264, 112589 (2021). Heris, M. P., Foks, N. L., Bagstad, K. J., Troy, A. & Ancona, Z. H. A rasterized building footprint dataset for the United States. Sci Data 7, 207 (2020). Liang, J., Gong, J. & Li, W. Applications and impacts of Google Earth: A decadal review (2006–2016). ISPRS Journal of Photogrammetry and Remote Sensing 146, 91–107 (2018). Taylor, J. R. & Lovell, S. T. Mapping public and private spaces of urban agriculture in Chicago through the analysis of high-resolution aerial images in Google Earth. Landscape and Urban Planning 108, 57–70 (2012). Yu, L. & Gong, P. Google Earth as a virtual globe tool for Earth science applications at the global scale: progress and perspectives. International Journal of Remote Sensing 33, 3966–3986 (2012). Kabir, Md, H., Endlicher, W. & Jägermeyr, J. Calculation of bright roof-tops for solar PV applications in Dhaka Megacity, Bangladesh. Renewable Energy 35, 1760–1764 (2010). Zhang, T., Huang, X., Wen, D. & Li, J. Urban Building Density Estimation From High-Resolution Imagery Using Multiple Features and Support Vector Regression. IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 10, 3265–3280 (2017). Zhu, Y., Huang, B., Gao, J., Huang, E. & Chen, H. Adaptive Polygon Generation Algorithm for Automatic Building Extraction. IEEE Trans. Geosci. Remote Sensing 60, 1–14 (2022). Sun, G. et al. Fusion of Multiscale Convolutional Neural Networks for Building Extraction in Very High-Resolution Images. Remote Sensing 11, 227 (2019). Cui, X. & Graf, H.-F. Recent land cover changes on the Tibetan Plateau: a review. Climatic Change 94, 47–61 (2009). Niu, D., Wang, L., Qiao, F. & Li, W. Analysis of Landscape Characteristics and Influencing Factors of Residential Areas on the Qinghai–Tibet Plateau: A Case Study of Tibet, China. IJERPH 19, 14951 (2022). Li, X. et al. Investigation and analysis of earthquake disasters of houses in the stricken areas of Maduo M7.4 earthquake in Qinghai Province. China Earthquake Engineering Journal 43, 896–902 (2021). Cui, P. & Jia, Y. Mountain hazards in the Tibetan Plateau: research status and prospects. National Science Review 2, 397–399 (2015). Wang, S., Che, Y. & Xinggang, M. Integrated risk assessment of glacier lake outburst flood (GLOF) disaster over the Qinghai–Tibetan Plateau (QTP). Landslides 17, 2849–2863 (2020). An, B. et al. Process, mechanisms, and early warning of glacier collapse-induced river blocking disasters in the Yarlung Tsangpo Grand Canyon, southeastern Tibetan Plateau. Science of The Total Environment 816, 151652 (2022). Huo, T. et al. Exploring the impact of urbanization on urban building carbon emissions in China: Evidence from a provincial panel data model. Sustainable Cities and Society 56, 102068 (2020). Li, M., Koks, E., Taubenböck, H. & Van Vliet, J. Continental-scale mapping and analysis of 3D building structure. Remote Sens. Environ. 245, 111859 (2020). Hossain, M. K. & Meng, Q. A fine-scale spatial analytics of the assessment and mapping of buildings and population at different risk levels of urban flood. Land Use Policy 99, 104829 (2020). Dolce, M. et al. Seismic risk assessment of residential buildings in Italy. Bull Earthquake Eng 19, 2999–3032 (2021). Liu, Y. et al. Design optimization of the solar heating system for office buildings based on life cycle cost in Qinghai-Tibet plateau of China. Energy 246, 123288 (2022). Yu, T. et al. Thermal performance of a heating system combining solar air collector with hollow ventilated interior wall in residential buildings on Tibetan Plateau. Energy 182, 93–109 (2019). Liu, Z., Wu, D., Yu, H., Ma, W. & Jin, G. Field measurement and numerical simulation of combined solar heating operation modes for domestic buildings based on the Qinghai–Tibetan plateau case. Energy and Buildings 167, 312–321 (2018). Mohajeri, N. et al. A city-scale roof shape classification using machine learning for solar energy applications. Renewable Energy 121, 81–93 (2018). Li, Z. et al. SinoLC-1: the first 1 m resolution national-scale land-cover map of China created with a deep learning framework and open-access data. Earth Syst. Sci. Data 15, 4749–4780 (2023). Yao, T. Tackling on environmental changes in Tibetan Plateau with focus on water, ecosystem and adaptation. Science Bulletin 64, 417 (2019). Qi, W., Liu, S. & Zhou, L. Regional differentiation of population in Tibetan Plateau: Insight from the ‘Hu Line’. Acta Geographica Sinica 75, 255–267 (2020). Zhao, Y. et al. Towards a common validation sample set for global land-cover mapping. International Journal of Remote Sensing 35, 4795–4814 (2014). Jiang, S. et al. An Optimized Deep Neural Network Detecting Small and Narrow Rectangular Objects in Google Earth Images.IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 13, 1068–1081 (2020). Wegner, J. D., Branson, S., Hall, D., Schindler, K. & Perona, P. Cataloging Public Objects Using Aerial and Street-Level Images — Urban Trees. in 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR) 6014–6023. https://doi.org/10.1109/CVPR.2016.647 (IEEE, Las Vegas, NV, USA, 2016). Yang, M. et al. Detecting and mapping tree crowns based on convolutional neural network and Google Earth images. International Journal of Applied Earth Observation and Geoinformation 108, 102764 (2022). Zhao, Q. et al. Progress and Trends in the Application of Google Earth and Google Earth Engine. Remote Sensing 13, 3778 (2021). Li, W. et al. Integrating Google Earth imagery with Landsat data to improve 30-m resolution land cover mapping. Remote Sens. Environ. 237, 111563 (2020). Venter, Z. S., Barton, D. N., Chakraborty, T., Simensen, T. & Singh, G. Global 10 m Land Use Land Cover Datasets: A Comparison of Dynamic World, World Cover and Esri Land Cover. Remote Sensing 14, 4101 (2022). Meng, X., Jiang, Z., Wang, X. & Long, Y. Shrinking cities on the globe: Evidence from LandScan 2000–2019. Environ Plan A 53, 1244–1248 (2021). Kirillov, A., Wu, Y., He, K. & Girshick, R. PointRend: Image Segmentation As Rendering. in 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 9796–9805. https://doi.org/10.1109/CVPR42600.2020.00982 (IEEE, Seattle, WA, USA, 2020). Levner, I. & Zhang, H. Classification-Driven Watershed Segmentation. IEEE Trans. on Image Process. 16, 1437–1445 (2007). Xue, Y., Zhao, J. & Zhang, M. A Watershed-Segmentation-Based Improved Algorithm for Extracting Cultivated Land Boundaries. Remote Sensing 13, 939 (2021). Xu, H. et al. Analytical Insight of Earth: A Cloud-Platform of Intelligent Computing for Geospatial Big Data. (2023). Ye, T., Shan, H., Wu, J. & Zhou, Q. Vectorized building roof-top prints of the Qinghai-Tibetan Plateau and its neighboring regions. National Tibetan Plateau Data Center National Tibetan Plateau Data Center https://doi.org/10.11888/RemoteSen.tpdc.301170 (2024). Ikotun, A. M., Ezugwu, A. E., Abualigah, L., Abuhaija, B. & Heming, J. K-means clustering algorithms: A comprehensive review, variants analysis, and advances in the era of big data. Information Sciences 622, 178–210 (2023). Liu, F. & Deng, Y. Determine the Number of Unknown Targets in Open World Based on Elbow Method. IEEE Trans. Fuzzy Syst. 29, 986–995 (2021). Zeng, C., Wang, J. & Lehrbass, B. An Evaluation System for Building Footprint Extraction From Remotely Sensed Data. IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 6, 1640–1652 (2013). Deng, X., Liu, Q., Deng, Y. & Mahadevan, S. An improved method to construct basic probability assignment based on the confusion matrix for classification problem. Information Sciences 340–341, 250–261 (2016). Hay, A. M. The derivation of global estimates from a confusion matrix. International Journal of Remote Sensing 9, 1395–1398 (1988). He, D., Shi, Q., Liu, X., Zhong, Y. & Zhang, X. Deep Subpixel Mapping Based on Semantic Information Modulated Network for Urban Land Use Mapping. IEEE Trans. Geosci. Remote Sensing 59, 10628–10646 (2021). Rivermap Company. https://rivermap.cn/. ESA WorldCover 10 m 2020 v100. https://zenodo.org/records/5571936. China National DEM 1km, 500m, and 250m data (based on 90 m SRTM). Resource and Environmental Science Data Platform https://www.resdc.cn/data.aspx?DATAID=123. ORNL LandScan Viewer - Oak Ridge National Laboratory. https://landscan.ornl.gov/. Xu, X. Annual NDVI and EVI 1km datasets in China. Resource and Environmental Science Data Platform https://www.resdc.cn/DOI/DOI.aspx?DOIID=49. Liu, Z., Tang, H., Feng, L. & Lyu, S. CBRA: The first multi-annual (2016–2021) and high-resolution (2.5 m) building rooftop area dataset in China derived with Super-resolution Segmentation from Sentinel-2 imagery. Zenodo https://doi.org/10.5281/zenodo.7500612 (2023). Acuto, M., Parnell, S. & Seto, K. C. Building a global urban science. Nat Sustain 1, 2–4 (2018). Nat Sustain 1 Biljecki, F., Arroyo Ohori, K., Ledoux, H., Peters, R. & Stoter, J. Population Estimation Using a 3D City Model: A Multi-Scale Country-Wide Study in the Netherlands. PLoS ONE 11, e0156808 (2016). PLoS ONE 11 Hu, Q., Zhen, L., Mao, Y., Zhou, X. & Zhou, G. Automated building extraction using satellite remote sensing imagery. Automation in Construction 123, 103509 (2021). Automation in Construction 123 Wu, J., Li, Y., Li, N. & Shi, P. Development of an Asset Value Map for Disaster Risk Assessment in China by Spatial Disaggregation Using Ancillary Remote Sensing Data. Risk Analysis 38, 17–30 (2018). Risk Analysis 38 Chen, Y., Tang, L., Yang, X., Bilal, M. & Li, Q. Object-based multi-modal convolution neural networks for building extraction using panchromatic and multispectral imagery. Neurocomputing 386, 136–146 (2020). Neurocomputing 386 Nouvel, R., Zirak, M., Coors, V. & Eicker, U. The influence of data quality on urban heating demand modeling using 3D city models. Computers, Environment and Urban Systems 64, 68–80 (2017). Computers, Environment and Urban Systems 64 He, T. et al. Global 30 meters spatiotemporal 3D urban expansion dataset from 1990 to 2010. Sci Data 10, 321 (2023). et al Sci Data 10 Liu, L. et al. Climate change impacts on planned supply–demand match in global wind and solar energy systems. Nat Energy https://doi.org/10.1038/s41560-023-01304-w (2023). et al Nat Energy https://doi.org/10.1038/s41560-023-01304-w Appolloni, E. et al. The global rise of urban rooftop agriculture: A review of worldwide cases. Journal of Cleaner Production 296, 126556 (2021). et al Journal of Cleaner Production 296 Assouline, D., Mohajeri, N. & Scartezzini, J.-L. Large-scale rooftop solar photovoltaic technical potential estimation using Random Forests. Applied Energy 217, 189–211 (2018). Applied Energy 217 Shepero, M., Munkhammar, J., Widén, J., Bishop, J. D. K. & Boström, T. Modeling of photovoltaic power generation and electric vehicles charging on city-scale: A review. Renewable and Sustainable Energy Reviews 89, 61–71 (2018). Renewable and Sustainable Energy Reviews 89 Liu, Z., Tang, H., Feng, L. & Lyu, S. China Building Rooftop Area: the first multi-annual (2016–2021) and high-resolution (2.5 m) building rooftop area dataset in China derived with super-resolution segmentation from Sentinel-2 imagery. Earth Syst. Sci. Data 15, 3547–3572 (2023). Earth Syst. Sci. Data 15 Zhang, Z. et al. Vectorized rooftop area data for 90 cities in China. Sci Data 9, 66 (2022). et al Sci Data 9 Wu, W.-B. et al. A first Chinese building height estimate at 10 m resolution (CNBH-10 m) using multi-source earth observations and machine learning. Remote Sens. Environ. 291, 113578 (2023). et al Remote Sens. Environ. 291 Brown, C. F. et al. Dynamic World, Near real-time global 10 m land use land cover mapping. Sci Data 9, 251 (2022). et al Sci Data 9 Karra, K. et al. Global land use/land cover with Sentinel 2 and deep learning. in 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS 4704–4707. https://doi.org/10.1109/IGARSS47720.2021.9553499 (IEEE, Brussels, Belgium, 2021). et al 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS https://doi.org/10.1109/IGARSS47720.2021.9553499 Zanaga, D. et al. ESA WorldCover 10 m 2020 v100. Zenodo https://doi.org/10.5281/zenodo.5571936 (2021). et al Zenodo https://doi.org/10.5281/zenodo.5571936 Jakubowski, M., Li, W., Guo, Q. & Kelly, M. Delineating Individual Trees from Lidar Data: A Comparison of Vector- and Raster-based Segmentation Approaches. Remote Sensing 5, 4163–4186 (2013). Remote Sensing 5 Guo, H., Shi, Q., Marinoni, A., Du, B. & Zhang, L. Deep building footprint update network: A semi-supervised method for updating existing building footprint from bi-temporal remote sensing images. Remote Sens. Environ. 264, 112589 (2021). Remote Sens. Environ. 264 Heris, M. P., Foks, N. L., Bagstad, K. J., Troy, A. & Ancona, Z. H. A rasterized building footprint dataset for the United States. Sci Data 7, 207 (2020). Sci Data 7 Liang, J., Gong, J. & Li, W. Applications and impacts of Google Earth: A decadal review (2006–2016). ISPRS Journal of Photogrammetry and Remote Sensing 146, 91–107 (2018). ISPRS Journal of Photogrammetry and Remote Sensing 146 Taylor, J. R. & Lovell, S. T. Mapping public and private spaces of urban agriculture in Chicago through the analysis of high-resolution aerial images in Google Earth. Landscape and Urban Planning 108, 57–70 (2012). Landscape and Urban Planning 108 Yu, L. & Gong, P. Google Earth as a virtual globe tool for Earth science applications at the global scale: progress and perspectives. International Journal of Remote Sensing 33, 3966–3986 (2012). International Journal of Remote Sensing 33 Kabir, Md, H., Endlicher, W. & Jägermeyr, J. Calculation of bright roof-tops for solar PV applications in Dhaka Megacity, Bangladesh. Renewable Energy 35, 1760–1764 (2010). Renewable Energy 35 Zhang, T., Huang, X., Wen, D. & Li, J. Urban Building Density Estimation From High-Resolution Imagery Using Multiple Features and Support Vector Regression. IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 10, 3265–3280 (2017). IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 10 Zhu, Y., Huang, B., Gao, J., Huang, E. & Chen, H. Adaptive Polygon Generation Algorithm for Automatic Building Extraction. IEEE Trans. Geosci. Remote Sensing 60, 1–14 (2022). IEEE Trans. Geosci. Remote Sensing 60 Sun, G. et al. Fusion of Multiscale Convolutional Neural Networks for Building Extraction in Very High-Resolution Images. Remote Sensing 11, 227 (2019). et al Remote Sensing 11 Cui, X. & Graf, H.-F. Recent land cover changes on the Tibetan Plateau: a review. Climatic Change 94, 47–61 (2009). Climatic Change 94 Niu, D., Wang, L., Qiao, F. & Li, W. Analysis of Landscape Characteristics and Influencing Factors of Residential Areas on the Qinghai–Tibet Plateau: A Case Study of Tibet, China. IJERPH 19, 14951 (2022). IJERPH 19 Li, X. et al. Investigation and analysis of earthquake disasters of houses in the stricken areas of Maduo M7.4 earthquake in Qinghai Province. China Earthquake Engineering Journal 43, 896–902 (2021). et al China Earthquake Engineering Journal 43 Cui, P. & Jia, Y. Mountain hazards in the Tibetan Plateau: research status and prospects. National Science Review 2, 397–399 (2015). National Science Review 2 Wang, S., Che, Y. & Xinggang, M. Integrated risk assessment of glacier lake outburst flood (GLOF) disaster over the Qinghai–Tibetan Plateau (QTP). Landslides 17, 2849–2863 (2020). Landslides 17 An, B. et al. Process, mechanisms, and early warning of glacier collapse-induced river blocking disasters in the Yarlung Tsangpo Grand Canyon, southeastern Tibetan Plateau. Science of The Total Environment 816, 151652 (2022). et al Science of The Total Environment 816 Huo, T. et al. Exploring the impact of urbanization on urban building carbon emissions in China: Evidence from a provincial panel data model. Sustainable Cities and Society 56, 102068 (2020). et al Sustainable Cities and Society 56 Li, M., Koks, E., Taubenböck, H. & Van Vliet, J. Continental-scale mapping and analysis of 3D building structure. Remote Sens. Environ. 245, 111859 (2020). Remote Sens. Environ. 245 Hossain, M. K. & Meng, Q. A fine-scale spatial analytics of the assessment and mapping of buildings and population at different risk levels of urban flood. Land Use Policy 99, 104829 (2020). Land Use Policy 99 Dolce, M. et al. Seismic risk assessment of residential buildings in Italy. Bull Earthquake Eng 19, 2999–3032 (2021). et al Bull Earthquake Eng 19 Liu, Y. et al. Design optimization of the solar heating system for office buildings based on life cycle cost in Qinghai-Tibet plateau of China. Energy 246, 123288 (2022). et al Energy 246 Yu, T. et al. Thermal performance of a heating system combining solar air collector with hollow ventilated interior wall in residential buildings on Tibetan Plateau. Energy 182, 93–109 (2019). et al Energy 182 Liu, Z., Wu, D., Yu, H., Ma, W. & Jin, G. Field measurement and numerical simulation of combined solar heating operation modes for domestic buildings based on the Qinghai–Tibetan plateau case. Energy and Buildings 167, 312–321 (2018). Energy and Buildings 167 Mohajeri, N. et al. A city-scale roof shape classification using machine learning for solar energy applications. Renewable Energy 121, 81–93 (2018). et al Renewable Energy 121 Li, Z. et al. SinoLC-1: the first 1 m resolution national-scale land-cover map of China created with a deep learning framework and open-access data. Earth Syst. Sci. Data 15, 4749–4780 (2023). et al Earth Syst. Sci. Data 15 Yao, T. Tackling on environmental changes in Tibetan Plateau with focus on water, ecosystem and adaptation. Science Bulletin 64, 417 (2019). Science Bulletin 64 Qi, W., Liu, S. & Zhou, L. Regional differentiation of population in Tibetan Plateau: Insight from the ‘Hu Line’. Acta Geographica Sinica 75, 255–267 (2020). Acta Geographica Sinica 75 Zhao, Y. et al. Towards a common validation sample set for global land-cover mapping. International Journal of Remote Sensing 35, 4795–4814 (2014). et al International Journal of Remote Sensing 35 Jiang, S. et al. An Optimized Deep Neural Network Detecting Small and Narrow Rectangular Objects in Google Earth Images.IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 13, 1068–1081 (2020). et al IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 13 Wegner, J. D., Branson, S., Hall, D., Schindler, K. & Perona, P. Cataloging Public Objects Using Aerial and Street-Level Images — Urban Trees. in 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR) 6014–6023. https://doi.org/10.1109/CVPR.2016.647 (IEEE, Las Vegas, NV, USA, 2016). 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR) https://doi.org/10.1109/CVPR.2016.647 Yang, M. et al. Detecting and mapping tree crowns based on convolutional neural network and Google Earth images. International Journal of Applied Earth Observation and Geoinformation 108, 102764 (2022). et al International Journal of Applied Earth Observation and Geoinformation 108 Zhao, Q. et al. Progress and Trends in the Application of Google Earth and Google Earth Engine. Remote Sensing 13, 3778 (2021). et al Remote Sensing 13 Li, W. et al. Integrating Google Earth imagery with Landsat data to improve 30-m resolution land cover mapping. Remote Sens. Environ. 237, 111563 (2020). et al Remote Sens. Environ. 237 Venter, Z. S., Barton, D. N., Chakraborty, T., Simensen, T. & Singh, G. Global 10 m Land Use Land Cover Datasets: A Comparison of Dynamic World, World Cover and Esri Land Cover. Remote Sensing 14, 4101 (2022). Remote Sensing 14 Meng, X., Jiang, Z., Wang, X. & Long, Y. Shrinking cities on the globe: Evidence from LandScan 2000–2019. Environ Plan A 53, 1244–1248 (2021). Environ Plan A 53 Kirillov, A., Wu, Y., He, K. & Girshick, R. PointRend: Image Segmentation As Rendering. in 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 9796–9805. https://doi.org/10.1109/CVPR42600.2020.00982 (IEEE, Seattle, WA, USA, 2020). 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) https://doi.org/10.1109/CVPR42600.2020.00982 Levner, I. & Zhang, H. Classification-Driven Watershed Segmentation. IEEE Trans. on Image Process. 16, 1437–1445 (2007). IEEE Trans. on Image Process. 16 Xue, Y., Zhao, J. & Zhang, M. A Watershed-Segmentation-Based Improved Algorithm for Extracting Cultivated Land Boundaries. Remote Sensing 13, 939 (2021). Remote Sensing 13 Xu, H. et al. Analytical Insight of Earth: A Cloud-Platform of Intelligent Computing for Geospatial Big Data. (2023). et al Ye, T., Shan, H., Wu, J. & Zhou, Q. Vectorized building roof-top prints of the Qinghai-Tibetan Plateau and its neighboring regions. National Tibetan Plateau Data Center National Tibetan Plateau Data Center https://doi.org/10.11888/RemoteSen.tpdc.301170 (2024). National Tibetan Plateau Data Center National Tibetan Plateau Data Center https://doi.org/10.11888/RemoteSen.tpdc.301170 Ikotun, A. M., Ezugwu, A. E., Abualigah, L., Abuhaija, B. & Heming, J. K-means clustering algorithms: A comprehensive review, variants analysis, and advances in the era of big data. Information Sciences 622, 178–210 (2023). Information Sciences 622 Liu, F. & Deng, Y. Determine the Number of Unknown Targets in Open World Based on Elbow Method. IEEE Trans. Fuzzy Syst. 29, 986–995 (2021). IEEE Trans. Fuzzy Syst. 29 Zeng, C., Wang, J. & Lehrbass, B. An Evaluation System for Building Footprint Extraction From Remotely Sensed Data. IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 6, 1640–1652 (2013). IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 6 Deng, X., Liu, Q., Deng, Y. & Mahadevan, S. An improved method to construct basic probability assignment based on the confusion matrix for classification problem. Information Sciences 340–341, 250–261 (2016). Information Sciences 340–341 Hay, A. M. The derivation of global estimates from a confusion matrix. International Journal of Remote Sensing 9, 1395–1398 (1988). International Journal of Remote Sensing 9 He, D., Shi, Q., Liu, X., Zhong, Y. & Zhang, X. Deep Subpixel Mapping Based on Semantic Information Modulated Network for Urban Land Use Mapping. IEEE Trans. Geosci. Remote Sensing 59, 10628–10646 (2021). IEEE Trans. Geosci. Remote Sensing 59 Rivermap Company. https://rivermap.cn/. https://rivermap.cn/ ESA WorldCover 10 m 2020 v100. https://zenodo.org/records/5571936. https://zenodo.org/records/5571936 China National DEM 1km, 500m, and 250m data (based on 90 m SRTM). Resource and Environmental Science Data Platform https://www.resdc.cn/data.aspx?DATAID=123. Resource and Environmental Science Data Platform https://www.resdc.cn/data.aspx?DATAID=123 ORNL LandScan Viewer - Oak Ridge National Laboratory. https://landscan.ornl.gov/. https://landscan.ornl.gov/ Xu, X. Annual NDVI and EVI 1km datasets in China. Resource and Environmental Science Data Platform https://www.resdc.cn/DOI/DOI.aspx?DOIID=49. Resource and Environmental Science Data Platform https://www.resdc.cn/DOI/DOI.aspx?DOIID=49 Liu, Z., Tang, H., Feng, L. & Lyu, S. CBRA: The first multi-annual (2016–2021) and high-resolution (2.5 m) building rooftop area dataset in China derived with Super-resolution Segmentation from Sentinel-2 imagery. Zenodo https://doi.org/10.5281/zenodo.7500612 (2023). Zenodo https://doi.org/10.5281/zenodo.7500612 Acknowledgements The authors gratefully acknowledge the free access to the ESA WorldCover v100 land-cover products provided by the European Space Agency, CBRA building area products provided by Beijing normal university and building footprint extraction algorithm provided by AI earth platform. They were also helped through excellent work by the Google Earth Engine team in maintaining the planetary-scale geospatial cloud platform. Financial support: This study was supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP, Grant No. 2019QZKK0906). This paper is available on nature under CC by 4.0 Deed (Attribution 4.0 International) license. This paper is available on nature under CC by 4.0 Deed (Attribution 4.0 International) license. available on nature