GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/pyproj_functions.py:242-289 (handler)

  The handler function that implements the get_utm_zone tool logic using pyproj to query UTM CRS info and extract the zone number from coordinates.

  @gis_mcp.tool()
  def get_utm_zone(coordinates: List[float]) -> Dict[str, Any]:
      """Get UTM zone for given coordinates."""
      try:
          import pyproj
          from pyproj.database import query_utm_crs_info
          lon, lat = coordinates
          crs_info_list = query_utm_crs_info(
              datum_name="WGS 84",  # Use "WGS 84" with space as per standard
              area_of_interest=pyproj.aoi.AreaOfInterest(
                  west_lon_degree=lon,
                  south_lat_degree=lat,
                  east_lon_degree=lon,
                  north_lat_degree=lat
              )
          )
          if not crs_info_list:
              raise ValueError("No UTM CRS found for the given coordinates")
          
          # Create CRS from the first matching CRSInfo
          crs_obj = pyproj.CRS.from_authority(crs_info_list[0].auth_name, crs_info_list[0].code)
          # Extract zone number from CRS name (e.g., "WGS 84 / UTM zone 10N" -> 10)
          import re
          zone_match = re.search(r'zone\s+(\d+)', crs_info_list[0].name, re.IGNORECASE)
          if zone_match:
              zone = int(zone_match.group(1))
          else:
              # Fallback: try to extract from authority code
              # EPSG codes for UTM: 32601-32660 (north), 32701-32760 (south)
              code = int(crs_info_list[0].code)
              if 32601 <= code <= 32660:  # Northern hemisphere
                  zone = code - 32600
              elif 32701 <= code <= 32760:  # Southern hemisphere
                  zone = code - 32700
              else:
                  raise ValueError("Could not extract valid UTM zone number from CRS")
          
          if zone < 1 or zone > 60:
              raise ValueError(f"Invalid UTM zone number: {zone}")
          
          return {
              "status": "success",
              "zone": zone,
              "message": "UTM zone retrieved successfully"
          }
      except Exception as e:
          logger.error(f"Error getting UTM zone: {str(e)}")
          raise ValueError(f"Failed to get UTM zone: {str(e)}")

• src/gis_mcp/pyproj_functions.py:19-30 (registration)

  MCP resource that lists 'get_utm_zone' among available CRS information operations, aiding tool discovery.

  @gis_mcp.resource("gis://crs/info")
  def get_crs_info_operations() -> Dict[str, List[str]]:
      """List available CRS information operations."""
      return {
          "operations": [
              "get_crs_info",
              "get_available_crs",
              "get_utm_zone",
              "get_utm_crs",
              "get_geocentric_crs"
          ]
      }

• src/gis_mcp/pyproj_functions.py:243-243 (schema)

  Type hints and docstring define the input schema (coordinates: List[float]) and output schema (Dict[str, Any]).

  def get_utm_zone(coordinates: List[float]) -> Dict[str, Any]: