GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/pyproj_functions.py:154-177 (handler)

  The handler function for the 'get_geod_info' tool, decorated with @gis_mcp.tool(). It creates a pyproj.Geod object and returns ellipsoid parameters (a, b, f, es, e).

  @gis_mcp.tool()
  def get_geod_info(ellps: str = "WGS84", a: Optional[float] = None,
                  b: Optional[float] = None, f: Optional[float] = None) -> Dict[str, Any]:
      """Get information about a geodetic calculation."""
      try:
          import pyproj
          geod = pyproj.Geod(ellps=ellps, a=a, b=b, f=f)
          # Calculate e (eccentricity) from es (first eccentricity squared)
          e = (geod.es ** 0.5) if geod.es >= 0 else None
          
          return {
              "status": "success",
              "ellps": ellps,  # Return the parameter, not attribute
              "ellipsoid": ellps,  # Also include as ellipsoid for compatibility
              "a": geod.a,
              "b": geod.b,
              "f": geod.f,
              "es": geod.es,
              "e": e,
              "message": "Geodetic information retrieved successfully"
          }
      except Exception as e:
          logger.error(f"Error getting geodetic info: {str(e)}")
          raise ValueError(f"Failed to get geodetic info: {str(e)}")

• src/gis_mcp/main.py:66-72 (registration)

  Import of pyproj_functions.py in the main entry point, which executes the @gis_mcp.tool() decorators to register the 'get_geod_info' tool with the FastMCP instance.

  from . import (
      geopandas_functions,
      shapely_functions,
      rasterio_functions,
      pyproj_functions,
      pysal_functions,
  )

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

  GIS resource that lists 'get_geod_info' as one of the available geodetic operations for discovery.

  @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"
          ]
      }