GIS MCP Server

Instructions

Implementation Reference

• src/gis_mcp/geopandas_functions.py:424-462 (handler)

  The core handler function decorated with @gis_mcp.tool(), implementing point-in-polygon check via geopandas.sjoin with 'within' predicate. Handles file I/O, CRS alignment, result preview, and optional output saving.

  @gis_mcp.tool()
  def point_in_polygon(points_path: str, polygons_path: str, output_path: str = None) -> Dict[str, Any]:
      """
      Check if points are inside polygons using spatial join (predicate='within').
      Args:
          points_path: Path to the point geospatial file.
          polygons_path: Path to the polygon geospatial file.
          output_path: Optional path to save the result.
      Returns:
          Dictionary with status, message, and output info.
      """
      try:
          points = gpd.read_file(points_path)
          polygons = gpd.read_file(polygons_path)
          if points.crs != polygons.crs:
              polygons = polygons.to_crs(points.crs)
          result = gpd.sjoin(points, polygons, how="left", predicate="within")
          if output_path:
              output_path_resolved = resolve_path(output_path, relative_to_storage=True)
              output_path_resolved.parent.mkdir(parents=True, exist_ok=True)
              result.to_file(str(output_path_resolved))
              output_path = str(output_path_resolved)
          # Convert geometry to WKT for serialization
          preview_df = result.head(5).copy()
          if 'geometry' in preview_df.columns:
              preview_df['geometry'] = preview_df['geometry'].apply(lambda g: g.wkt if g is not None else None)
          preview = preview_df.to_dict(orient="records")
          return {
              "status": "success",
              "message": "Point-in-polygon test completed successfully.",
              "num_features": len(result),
              "crs": str(result.crs),
              "columns": list(result.columns),
              "preview": preview,
              "output_path": output_path,
          }
      except Exception as e:
          logger.error(f"Error in point_in_polygon: {str(e)}")
          return {"status": "error", "message": str(e)}

• src/gis_mcp/geopandas_functions.py:28-39 (registration)

  MCP resource listing that registers 'point_in_polygon' as an available operation in the geopandas/joins category.

  @gis_mcp.resource("gis://geopandas/joins")
  def get_geopandas_joins() -> Dict[str, List[str]]:
      """List available GeoPandas join operations."""
      return {
          "operations": [
              "append_gpd",
              "merge_gpd",
              "sjoin_gpd",
              "sjoin_nearest_gpd",
              "point_in_polygon"
          ]
      }