CCWEM_CCWIF

<p dir="ltr"><b>CCWEM and CCWIF are two complementary 10 m spatial datasets describing the extent and internal inundation-frequency gradients of China’s coastal wetlands in 2025. </b></p><p dir="ltr">The China Coastal Wetland Extent Map (CCWEM) delineates the maximum extent of natural coastal wetlands, including tidal flats, salt marshes, and mangroves. The vector dataset contains 12 province-level polygon features and attributes describing region identifier, coastal wetland area, and province/region name. </p><p dir="ltr">The China Coastal Wetland Inundation Frequency Map (CCWIF) further characterizes relative inundation-frequency gradients within the CCWEM extent.

It contains five annual inundation-duration classes: <30 d, 30–90 d, 90–180 d, 180–300 d, and >300 d. The vector dataset contains 60 polygon features corresponding to 12 coastal regions and five inundation-frequency classes. </p><p dir="ltr">Both datasets use the Asia North Albers Equal Area Conic coordinate reference system (ESRI:102025; WGS 1984 datum), with coordinates expressed in metres and UTF-8 character encoding.