# Cnmaps Python Assistant > Use when the user is writing or debugging Python code with cnmaps, including compliant boundary data aligned with China's territorial claims, China province/city/district boundaries, and global country or region boundary plotting, Cartopy administrative overlays, raster masking to an administrative region, or scientific map workflows that combine cnmaps with cartopy, matplotlib, or xarray. - Skill: `tomevault-io/cnmaps-python-assistant` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/cnmaps-python-assistant` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/cnmaps-python-assistant/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/cnmaps-python-assistant --- # cnmaps Skill Overview Use this guidance when helping with Python code that uses `cnmaps`, especially for compliant boundary data aligned with China's territorial claims, Chinese administrative boundaries, global country or region boundaries, Cartopy overlays, Matplotlib map rendering, raster masking ideas, and workflows that combine `cnmaps` with `cartopy`, `matplotlib`, or `xarray`. ## When to Use This Skill - The user mentions `cnmaps` directly. - The user wants to draw China, province, city, district, or global country and region boundaries. - The user wants to overlay administrative boundaries on a `cartopy` map. - The user wants to mask, clip, or constrain raster-like scientific data to an administrative boundary. - The user needs help deciding which `cnmaps` function to use for querying boundaries, plotting, clipping, or centroid labeling. - The user needs to understand whether a returned object can be passed into `cartopy`, `matplotlib`, or a downstream masking workflow. ## What Claude Should Do - First classify the task as one of: boundary lookup, overlay plotting, raster mask/clip workflow, centroid labeling, or multi-library integration. - Prefer real `cnmaps` APIs over guessed names. Use the supporting reference files before inferring missing details. - If the user already knows several exact province, city, district, or country names, prefer one batch `get_adm_maps(...)` query with a list filter over many separate calls. - When the task involves plotting, reason about the full stack: `cnmaps` objects, `cartopy` projection, Matplotlib axes, and how geometries are passed through. - When the task involves raster clipping or masking, be explicit that `cnmaps` mainly provides boundary and geometry-side helpers; the full raster workflow may also involve NumPy, xarray, or Matplotlib objects. - When the environment may not be ready, distinguish missing `cnmaps`, missing plotting dependencies, and missing data-provider discovery. ## cnmaps Knowledge Model Treat `cnmaps` as a Python function library for querying compliant boundary data aligned with China's territorial claims, retrieving geometries and centroid coordinates, drawing boundaries, and helping boundary-guided scientific plotting workflows. It is not limited to China-only maps: it also supports global country and region boundaries. Do not describe it as a CLI-first tool. Many useful tasks require combining it with `cartopy`, `matplotlib`, NumPy, or xarray rather than expecting one black-box command. ## How to Work with Supporting Files - Read `references/api-overview.md` when you need the package capability map. - Read `references/workflows.md` when you need to choose a task-specific approach. - Read `references/return-types.md` when you need to reason about what `get_adm_maps` or related APIs return and how those objects connect to downstream libraries. - Read `references/common-pitfalls.md` when you need to avoid API hallucinations or common integration mistakes. - Read `references/capability-boundaries.md` when you need to explain what `cnmaps` handles directly versus what still belongs to Cartopy, Matplotlib, NumPy, xarray, or external GIS tools. - Prefer the files in `examples/` when producing runnable code for users. ## Output Requirements - Prefer Python code that is directly runnable or needs only small project-specific edits. - Briefly explain why a chosen `cnmaps` function or workflow fits the task. - If the task involves `cartopy`, `matplotlib`, or `xarray`, include the necessary surrounding code instead of only showing the `cnmaps` call. - Do not invent functions, return types, or module paths that are not confirmed. - Do not describe `cnmaps` as if it were a standalone terminal command for boundary processing. ## Common Failure Modes - Treating `cnmaps` as a unified CLI tool instead of a Python library. - Confusing boundary geometries with raster arrays. - Ignoring the `cartopy` projection and axes context in plotting code. - Recomputing centroids from geometry when `MapRecord` already exposes `longitude` and `latitude`. - Guessing return types or function signatures without checking the supporting references. --- > Source: [cnmetlab/cnmaps](https://github.com/cnmetlab/cnmaps) — distributed by [TomeVault](https://tomevault.io).