GHM Coastal Wetlands Dataset: A long-term and high-resolution coastal wetlands distribution dataset in the Guangdong-Hong Kong-Macao Area

The GHM Coastal Wetlands Dataset (GHMCWD) is a 30 m resolution map depicting the spatial distribution of forest, mangrove, swamp/marsh, tidal flat, reservoir/lake, breeding pond/pond, coastal water/river, impervious/ bare land and paddy field/grass in the Guangdong-Hong Kong-Macao area (GHM) from 1993 to 2023. This dataset is formatted in GeoTIFF and uses the WGS_1984 coordinate system (EPSG:4326). Pixel values are classified as follows: 10 for forest, 20 for mangrove, 30 for swamp/marsh, 40 for tidal flat, 50 for reservoir/lake, 70 for breeding pond/pond, 80 for coastal water/river, 90 for impervious/ bare land and 100 for paddy field/grass. The accuracy assessment indicates the overall accuracy and Kappa coefficients exceeding 0.9, with inter-annual accuracy variations of less than 5%.