PostGIS MCP Server

Instructions

Implementation Reference

• server.ts:1842-1882 (handler)

  The handler function for the 'extract-raster-value' tool. It parses input using the schema, sanitizes table/raster column names, executes a PostGIS query using ST_Value and ST_Intersects to extract raster pixel value at given longitude/latitude coordinates, and returns the results including value, band1 value, num_bands, and intersection status.

  case "extract-raster-value": {
    const { table_name, longitude, latitude, raster_column } =
      ExtractRasterValueSchema.parse(args);
  
    const sanitizedTableName = table_name.replace(/[^a-zA-Z0-9_]/g, "");
    const sanitizedRasterColumn = raster_column || "rast";
  
    const result = await client.query(
      `
      SELECT 
        ST_Value(${sanitizedRasterColumn}, ST_SetSRID(ST_MakePoint($1, $2), 4326)) as raster_value,
        ST_Value(${sanitizedRasterColumn}, 1, ST_SetSRID(ST_MakePoint($1, $2), 4326)) as band1_value,
        ST_NumBands(${sanitizedRasterColumn}) as num_bands
      FROM ${sanitizedTableName}
      WHERE ST_Intersects(${sanitizedRasterColumn}, ST_SetSRID(ST_MakePoint($1, $2), 4326))
      LIMIT 1;
    `,
      [longitude, latitude]
    );
  
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(
            {
              table_name: sanitizedTableName,
              raster_column: sanitizedRasterColumn,
              coordinates: [longitude, latitude],
              raster_value: result.rows[0]?.raster_value || null,
              band1_value: result.rows[0]?.band1_value || null,
              num_bands: result.rows[0]?.num_bands || 0,
              found_intersection: result.rows.length > 0,
            },
            null,
            2
          ),
        },
      ],
    };
  }

• server.ts:125-130 (schema)

  Zod schema defining the input parameters for the 'extract-raster-value' tool: table_name (required), longitude (required), latitude (required), raster_column (optional, defaults to 'rast'). Used for validation in the handler.

  const ExtractRasterValueSchema = z.object({
    table_name: z.string(),
    longitude: z.number(),
    latitude: z.number(),
    raster_column: z.string().optional().default("rast"),
  });

• server.ts:936-951 (registration)

  Registration of the 'extract-raster-value' tool in the ListToolsRequestHandler response. Defines the tool name, description, and inputSchema matching the Zod schema.

    name: "extract-raster-value",
    description: "Belirli koordinattaki raster değerini çıkar",
    inputSchema: {
      type: "object",
      properties: {
        table_name: { type: "string", description: "Raster tablosu" },
        longitude: { type: "number", description: "Boylam" },
        latitude: { type: "number", description: "Enlem" },
        raster_column: {
          type: "string",
          description: "Raster kolonu (varsayılan: rast)",
        },
      },
      required: ["table_name", "longitude", "latitude"],
    },
  },