Global High-Resolution Oasis Dataset

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 such as NDVI, and digital elevation models.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 generally 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 improve spatial consistency and reduce interpreter-related uncertainty.The dataset identifies 3,437 independent oasis patches worldwide, with a total area of 2,272,595.47 km², accounting for approximately 3.69% of global arid and semi-arid regions and about 1.50% of the global land surface.