GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/rasterio_functions.py:119-163 (handler)

  The primary handler function for the 'focal_statistics' MCP tool. It computes focal statistics (mean, min, max, std) on raster data using a moving window via scipy.ndimage.generic_filter. The function is registered via the @gis_mcp.tool() decorator, which handles schema generation from type hints and docstring.

  @gis_mcp.tool()
  def focal_statistics(raster_path: str, statistic: str, size: int = 3, output_path: str = None) -> Dict[str, Any]:
      """
      Compute focal (moving window) statistics on a raster.
      Args:
          raster_path: Path to the input raster.
          statistic: Statistic to compute ('mean', 'min', 'max', 'std').
          size: Window size (odd integer).
          output_path: Optional path to save the result.
      Returns:
          Dictionary with status, message, and output path if saved.
      """
      try:
          import rasterio
          import numpy as np
          from scipy.ndimage import generic_filter
          with rasterio.open(raster_path) as src:
              data = src.read(1)
              profile = src.profile.copy()
              func = None
              if statistic == "mean":
                  func = np.mean
              elif statistic == "min":
                  func = np.min
              elif statistic == "max":
                  func = np.max
              elif statistic == "std":
                  func = np.std
              else:
                  raise ValueError(f"Unsupported statistic: {statistic}")
              filtered = generic_filter(data, func, size=size, mode='nearest')
          if output_path:
              output_path_resolved = resolve_path(output_path, relative_to_storage=True)
              output_path_resolved.parent.mkdir(parents=True, exist_ok=True)
              with rasterio.open(str(output_path_resolved), "w", **profile) as dst:
                  dst.write(filtered, 1)
              output_path = str(output_path_resolved)
          return {
              "status": "success",
              "message": f"Focal {statistic} computed successfully.",
              "output_path": output_path
          }
      except Exception as e:
          logger.error(f"Error in focal_statistics: {str(e)}")
          return {"status": "error", "message": str(e)}

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

  Imports the rasterio_functions module (among others), which triggers the execution of decorators like @gis_mcp.tool() on functions such as focal_statistics, thereby registering the tool with the FastMCP server instance.

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

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

  A resource endpoint that lists available rasterio operations, including 'focal_statistics', for 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/rasterio_functions.py:120-130 (schema)

  The function signature and docstring define the input schema (parameters with types and descriptions) and output schema for the tool, used by FastMCP for validation.

  def focal_statistics(raster_path: str, statistic: str, size: int = 3, output_path: str = None) -> Dict[str, Any]:
      """
      Compute focal (moving window) statistics on a raster.
      Args:
          raster_path: Path to the input raster.
          statistic: Statistic to compute ('mean', 'min', 'max', 'std').
          size: Window size (odd integer).
          output_path: Optional path to save the result.
      Returns:
          Dictionary with status, message, and output path if saved.
      """