GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/rasterio_functions.py:317-362 (handler)

  The core handler function for the 'get_raster_crs' tool. It opens a raster file (local or URL), extracts its CRS using rasterio, and returns it in PROJ.4 dictionary and WKT formats.

  def get_raster_crs(path_or_url: str) -> Dict[str, Any]:
      """
      Retrieve the Coordinate Reference System (CRS) of a raster dataset.
      
      Opens the raster (local path or HTTPS URL), reads its DatasetReader.crs
      attribute as a PROJ.4-style dict, and also returns the WKT representation.
      """
      try:
          import numpy as np
          import rasterio
  
          # Strip backticks if the client wrapped the input in them
          cleaned = path_or_url.replace("`", "")
  
          # Open remote or local dataset
          if cleaned.lower().startswith("https://"):
              src = rasterio.open(cleaned)
          else:
              local_path = os.path.expanduser(cleaned)
              if not os.path.isfile(local_path):
                  raise FileNotFoundError(f"Raster file not found at '{local_path}'.")
              src = rasterio.open(local_path)
  
          # Access the CRS object on the opened dataset
          crs_obj = src.crs
          src.close()
  
          if crs_obj is None:
              raise ValueError("No CRS defined for this dataset.")
  
          # Convert CRS to PROJ.4‐style dict and WKT string
          proj4_dict = crs_obj.to_dict()    # e.g., {'init': 'epsg:32618'}
          wkt_str    = crs_obj.to_wkt()     # full WKT representation
  
          return {
              "status":      "success",
              "proj4":       proj4_dict,
              "wkt":         wkt_str,
              "message":     "CRS retrieved successfully"
          }
  
      except Exception as e:
          # Log and re-raise as ValueError for MCP error propagation
          logger.error(f"Error retrieving CRS for '{path_or_url}': {e}")
          raise ValueError(f"Failed to retrieve CRS: {e}")

• src/gis_mcp/rasterio_functions.py:11-35 (helper)

  Helper resource that lists 'get_raster_crs' among available rasterio operations, aiding in tool discovery.

  @gis_mcp.resource("gis://operation/rasterio")
  def get_rasterio_operations() -> Dict[str, List[str]]:
      """List available rasterio operations."""
      return {
          "operations": [
              "metadata_raster",
              "get_raster_crs",
              "clip_raster_with_shapefile",
              "resample_raster",
              "reproject_raster",
              "weighted_band_sum",
              "concat_bands",
              "raster_algebra",
              "compute_ndvi",
              "raster_histogram",
              "tile_raster",
              "raster_band_statistics",
              "extract_band",
              "zonal_statistics",
              "reclassify_raster",
              "focal_statistics",
              "hillshade",
              "write_raster"
          ]
      }

• src/gis_mcp/mcp.py:1-6 (registration)

  Definition of the FastMCP instance 'gis_mcp' used to register all tools via decorators.

  # MCP imports using the new SDK patterns
  from fastmcp import FastMCP
  
  
  gis_mcp = FastMCP("GIS MCP")

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

  Import of rasterio_functions module in main.py, which triggers registration of the get_raster_crs tool via its @gis_mcp.tool() decorator.

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