Global High-Resolution Oasis Dataset

The Global High-Resolution Oasis Dataset provides a globally consistent vector representation of oasis distributions for the reference year 2020. The dataset was produced through systematic manual visual interpretation of metre- to sub-metre-scale very-high-resolution satellite imagery available via Google Earth Pro, supported by multiple auxiliary geospatial datasets, including global land-cover products, vegetation indices (NDVI), and digital elevation models (DEM).Oasis boundaries were delineated based on continuous and stable vegetation cover and associated human productive activities within arid and semi-arid regions. To reduce the influence of seasonal variability and image quality differences, summer imagery from 2020 was preferentially used, with cloud cover strictly limited to less than 10%. Where suitable imagery from the reference year was unavailable, images from the temporally closest year with higher quality were adopted. All interpretations followed unified technical guidelines and were subject to cross-validation procedures to ensure spatial consistency.The dataset identifies 3,445 independent oasis patches worldwide, with a total area of approximately 2.28 × 10⁶ km², accounting for about 3.7% of global arid and semi-arid regions and approximately 1.5% of the global land surface. Oasis polygons are distributed across five continents and 54 countries, mainly concentrated in mid- to low-latitude dryland regions. Each oasis patch is represented as a polygon feature with associated geometric attributes, including area, perimeter, and centroid coordinates.To enhance data organization, retrieval, and long-term maintenance, each oasis patch is assigned a unique identifier based on a unified global oasis coding system. The coding scheme integrates four core geographic attributes—continent, country, river basin, and area-based ranking—which together characterize the key spatial properties of global oases and support multi-scale spatial analysis and dataset versioning.The dataset is managed using the WGS 84 geographic coordinate system and is organized into nine geographic regional subsets to improve accessibility and computational efficiency. This dataset provides a robust spatial baseline for global dryland studies, oasis spatial analysis, and the validation of global land-cover products in arid regions.