cgcs2000国家2000坐标系

Explain and work with the CGCS2000 coordinate reference system for China geospatial workflows, including EPSG:4490 interpretation, projected CRS selection, G...

Security Scan

An instruction-only GIS helper about the CGCS2000 coordinate system; its requirements and instructions match its stated purpose and it does not request credentials, install code, or call external endpoints.

Purpose & Capability

The skill's name/description (CGCS2000 / EPSG:4490 guidance) aligns with the provided instructions and reference material. It does not request unrelated credentials, binaries, or system access that would be out of scope for a CRS guidance skill.

Instruction Scope

SKILL.md stays on-topic: it describes how to interpret CRS forms, asks the agent to confirm input units/source, warns about GCJ-02/BD-09, and recommends QGIS for file-based reprojection. It does not instruct reading arbitrary host files, sending data to external endpoints, or accessing secrets. It references a local reference file included in the skill, which is appropriate.

Install Mechanism

There is no install spec and no code to write or execute — the skill is instruction-only. That minimizes disk/remote-code risk.

Credentials

The skill requires no environment variables, credentials, or config paths. All required information (CRS rules, reference doc) is contained in the skill files; nothing asks for unrelated secrets or system access.

Persistence & Privilege

Flags show default behavior: not always-enabled and user-invocable. The included agents/openai.yaml sets allow_implicit_invocation: true (permitting implicit invocation), which is normal for helper skills and not a concern by itself given the absence of other risks.

Assessment

This skill is an informational helper and appears internally consistent. It does not install code or ask for credentials. Before using it, (1) avoid pasting private credentials or proprietary data into prompts, (2) if you need file-based reprojection, run QGIS or other tools locally (the skill only recommends that), and (3) verify any CRS/EPSG codes the skill suggests against your official project/specs when survey-grade accuracy is required.

CGCS2000

Use this skill for practical reasoning about the China Geodetic Coordinate System 2000.

CGCS2000 is a China-centered geodetic reference framework used widely in surveying, mapping, and domestic GIS workflows. In many GIS tools, the geographic form is commonly represented as EPSG:4490, but real work often also involves projected CGCS2000 variants, especially Gauss-Kruger zone systems.

What This Skill Does

• Explain what CGCS2000 is and when it is the right source or target CRS.
• Distinguish geographic CGCS2000 from projected CGCS2000 variants.
• Identify whether the user likely means EPSG:4490 or a projected China CRS in meters.
• Check for common mistakes involving axis order, units, and false assumptions about "same as WGS84".
• Compare CGCS2000 with WGS84, GCJ-02, and BD-09.
• Recommend whether to keep the data in geographic coordinates or move to a projected CRS for analysis.
• Hand off file-based conversion and batch reprojection steps to qgis when execution is needed.

Standard Workflow

1. Confirm the actual input form:
   • longitude/latitude in degrees
   • projected easting/northing in meters
   • map-app coordinates that may actually be GCJ-02 or BD-09
2. Ask whether the user needs:
   • storage or exchange
   • web display
   • engineering, surveying, or measurement
   • file-based reprojection
3. State the exact CRS level being discussed:
   • CGCS2000 datum/reference frame
   • EPSG:4490 geographic CRS
   • projected CGCS2000 CRS with zone/projection details
4. Validate units and order before recommending conversion.
5. If the task needs meters, recommend the exact projected CRS rather than only saying "CGCS2000".

Decision Rules

• Use EPSG:4490 when the data is truly geographic CGCS2000 longitude/latitude in degrees.
• For engineering, cadastral, measurement, or local analysis work, prefer the correct projected CGCS2000 CRS in meters.
• Do not say "CGCS2000" alone when the task requires a projected CRS; include zone/projection details.
• Do not treat GCJ-02 or BD-09 as standard CGCS2000 coordinates.
• Do not assume consumer-map coordinates in China are raw CGCS2000 or raw WGS84.
• If the source is unknown, explicitly call out datum/projection uncertainty before suggesting a transformation.

Common Cases

The user says "CGCS2000 coordinates"

Interpret carefully:

• It may mean EPSG:4490 longitude/latitude in degrees.
• It may mean a projected CGCS2000 coordinate system in meters.
• It may be shorthand from a local data specification that still requires the exact EPSG or projection name.

The user wants to compare CGCS2000 and WGS84

• They are close for many practical GIS use cases, but they are not interchangeable by definition in every precise workflow.
• If regulatory, survey, or engineering accuracy matters, keep the stated source datum and use the required official CRS.
• If the task is generic storage or API exchange, explain whether the downstream system expects CGCS2000 or WGS84 explicitly.

The user has China map coordinates from an app

• First check whether the source is actually GCJ-02 or BD-09.
• Do not label app-map coordinates as CGCS2000 without evidence.
• If the request is about web maps or app SDKs, mention offset-system ambiguity early.

The user wants projected analysis

• Ask for the area of use and the current CRS.
• Recommend the exact projected CGCS2000 CRS with units in meters.
• If the user only has files and wants execution, use qgis.

What To Return

• The interpreted source CRS, with exact name or EPSG when possible.
• Whether the coordinates are likely geographic degrees or projected meters.
• Whether EPSG:4490 is appropriate, or whether a projected CGCS2000 CRS is needed instead.
• Any risk that the data is actually GCJ-02 or BD-09.
• A concrete next step for reprojection, exchange, or validation.

When Not To Use

• Reverse geocoding or address lookup: use geocode.
• QGIS file-based processing or batch reprojection: use qgis.
• General CRS comparison across many systems when CGCS2000 is not the focus: use project.
• GPS-only WGS84 validation with no China-specific CRS question: use wgs84.

OpenClaw + ClawHub Notes

• Keep examples generic and standards-based.
• Do not hardcode private datasets, machine paths, credentials, or proprietary basemap assumptions.
• For clawhub.ai publication, keep examples reproducible and version/changelog updates semver-driven.

Reference Docs In This Skill

• Read {baseDir}/references/cgcs2000-reference.md for quick comparison points, projected-workflow guidance, and common failure cases.