Skip to main content
Glama

calculate_geodetic_area

Calculate polygon area using geodetic methods for accurate geospatial analysis in GIS applications.

Instructions

Calculate area of a polygon using geodetic calculations.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
geometryYes
ellpsNoWGS84

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Implementation Reference

  • Main handler function for the 'calculate_geodetic_area' tool. Parses WKT geometry, uses pyproj.Geod.geometry_area_perimeter to compute the geodetic area on the specified ellipsoid, and returns the result in square meters.
    @gis_mcp.tool()
    def calculate_geodetic_area(geometry: str, ellps: str = "WGS84") -> Dict[str, Any]:
        """Calculate area of a polygon using geodetic calculations."""
        try:
            import pyproj
            from shapely import wkt
            geod = pyproj.Geod(ellps=ellps)
            polygon = wkt.loads(geometry)
            area = abs(geod.geometry_area_perimeter(polygon)[0])
            return {
                "status": "success",
                "area": float(area),
                "ellps": ellps,
                "unit": "square_meters",
                "message": "Geodetic area calculated successfully"
            }
        except Exception as e:
            logger.error(f"Error calculating geodetic area: {str(e)}")
            raise ValueError(f"Failed to calculate geodetic area: {str(e)}")
  • Resource listing that includes 'calculate_geodetic_area' as one of the available geodetic operations.
    @gis_mcp.resource("gis://crs/geodetic")
    def get_geodetic_operations() -> Dict[str, List[str]]:
        """List available geodetic operations."""
        return {
            "operations": [
                "get_geod_info",
                "calculate_geodetic_distance",
                "calculate_geodetic_point",
                "calculate_geodetic_area"
            ]
        }
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the calculation method but lacks details on permissions, rate limits, error handling, or output format. For a computational tool with no annotation coverage, this leaves significant gaps in understanding its behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that directly states the tool's purpose. It's front-loaded with no unnecessary words, making it easy to parse quickly. Every part of the sentence earns its place by specifying the action and method.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (geodetic calculations), no annotations, and an output schema present, the description is minimally adequate. It covers the core purpose but lacks details on parameters, behavioral traits, and usage context. The output schema helps, but the description doesn't fully compensate for missing annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate but adds no parameter information. It doesn't explain what 'geometry' should contain (e.g., GeoJSON, WKT) or what 'ellps' does beyond its default. With 2 parameters undocumented in both schema and description, this is inadequate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb ('calculate') and resource ('area of a polygon'), specifying it uses geodetic calculations. It distinguishes from sibling 'get_area' by emphasizing geodetic methods, though it doesn't explicitly contrast with other geometric tools like 'get_bounds' or 'get_centroid'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention when geodetic calculations are preferred over planar methods, nor does it reference sibling tools like 'get_area' or 'calculate_geodetic_distance' for context. Usage is implied only by the tool name and description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/mahdin75/gis-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server