GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/shapely_functions.py:486-511 (handler)

  The core handler function for the 'snap_geometry' tool. It is registered via the @gis_mcp.tool() decorator and implements snapping two geometries using Shapely's snap operation with the given tolerance. Includes input validation implicitly through type hints and docstring, and returns WKT geometry or error.

  @gis_mcp.tool()
  def snap_geometry(geometry1: str, geometry2: str, tolerance: float) -> Dict[str, Any]:
      """
      Snap one geometry to another using shapely.ops.snap.
      Args:
          geometry1: WKT string of the geometry to be snapped.
          geometry2: WKT string of the reference geometry.
          tolerance: Distance tolerance for snapping.
      Returns:
          Dictionary with status, message, and snapped geometry as WKT.
      """
      try:
          from shapely import wkt
          from shapely.ops import snap
          geom1 = wkt.loads(geometry1)
          geom2 = wkt.loads(geometry2)
          snapped = snap(geom1, geom2, tolerance)
          return {
              "status": "success",
              "geometry": snapped.wkt,
              "message": "Geometry snapped successfully"
          }
      except Exception as e:
          logger.error(f"Error in snap_geometry: {str(e)}")
          return {"status": "error", "message": str(e)}

• src/gis_mcp/shapely_functions.py:82-93 (registration)

  MCP resource that lists 'snap_geometry' among available Shapely utility operations, serving as a discovery mechanism for the tool.

  @gis_mcp.resource("gis://operations/shapely_util")
  def get_shapely_util_operations() -> Dict[str, List[str]]:
      """List available Shapely utility/advanced operations."""
      return {
          "operations": [
              "snap_geometry",
              "nearest_point_on_geometry",
              "normalize_geometry",
              "geometry_to_geojson",
              "geojson_to_geometry"
          ]
      }

• src/gis_mcp/shapely_functions.py:509-510 (helper)

  Error logging specific to snap_geometry, but minor.

  logger.error(f"Error in snap_geometry: {str(e)}")
  return {"status": "error", "message": str(e)}