GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/pyproj_functions.py:222-240 (handler)

  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)}")

• src/gis_mcp/pyproj_functions.py:32-42 (registration)

  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"
          ]
      }