CHGIS TGAZ

Query the China Historical GIS Temporal Gazetteer for historical placenames and administrative units (222 BCE–1911 CE).

Critical: Things Claude Won't Know Without This Skill

The correct domain is chgis.hudci.org — the old maps.cga.harvard.edu is defunct. Do not use it.

ID lookups use a URL path format, NOT query params:

✅  https://chgis.hudci.org/tgaz/placename/json/hvd_32180
❌  https://chgis.hudci.org/tgaz/placename?id=hvd_32180&fmt=json

The ?fmt=json parameter only works for the faceted search endpoint.

TGAZ IDs use the hvd_ prefix: CHGIS ID 32180 → TGAZ ID hvd_32180.

The ipar (parent) search parameter is unreliable. For hierarchical queries (e.g., "find all counties in Zhejiang"), use the canonical record drill-down approach instead: look up the parent record by ID and read its subordinate units. A record lists only the next level down. A province lists prefectures, not counties, so counties need a second step (see "Hierarchical Queries").