China temporal administrative map: a multitemporal database for Chinese historical administrative divisions (2009–2023)

Administrative divisions in China have experienced frequent modifications, presenting significant challenges for researchers requiring accurate historical administrative data. We present CTAmap (China Temporal Sequence Administrative Map), a comprehensive multi-temporal database documenting Chinese administrative divisions from 2009 to 2023. This database integrates authoritative data sources, including the Chinese National Fundamental Geographic Information Database (NGCC) and the Ministry of Civil Affairs (MCA) administrative division code, while employing a systematic workflow to reconstruct administrative divisions through both forward and backward temporal derivation from a 2020 baseline. CTAmap provides full coverage across provincial-level, prefectural-level, and county-level, maintaining complete correspondence with official administrative codes and hierarchical relationships. Each administrative unit contains standardized bilingual attributes (Simplified Chinese and English), including official names, administrative codes, and temporal validity. Our analysis reveals significant trends in China's administrative evolution, including the stability of prefecture-level divisions (332-334 units) contrasting with the dynamic modifications at the county-level (decreasing from 2,859 to 2,843 units). Compared to existing databases like GADM(Global Administrative Areas) and UC Berkeley Dataset, CTAmap demonstrates superior accuracy and consistency with official statistics. While GADM shows significant discrepancies (reporting only 2,421 county-level units versus the official 2,843 in 2022), and the UC Berkeley Dataset exhibits geometric variations, CTAmap maintains complete consistency with MCA statistics across all administrative levels. The database offers standardized spatial data representation, continuous temporal coverage, and comprehensive change documentation, serving as a valuable resource for spatial analysis, policy research, and socioeconomic studies requiring historical administrative boundary data in China.