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    "# More about areas and pyresample\n",
    "\n",
    "## Summary\n",
    "\n",
    "In this tutorial, we will learn more about defining areas to work with in pytroll/satpy, and how to save them for later use.\n",
    "\n",
    "## Defining Area Definitions\n",
    "\n",
    "The areas in pytroll/satpy are defined through the pyresample package.\n",
    "\n",
    "To define an area, have a look at the pyresample documentation:\n",
    "https://pyresample.readthedocs.io/en/latest/geo_def.html\n",
    "\n",
    "In this tutorial, we will create an area definition that covers Sweden, following the official SWEREF99TM.\n",
    "\n",
    "The projection to use is transverse mercator, with the following parameter:\n",
    "- reference longitude is 15\n",
    "- scale factor is 0.9996\n",
    "\n",
    "Sweden is included in a lon/lat box spanning approximately 10 to 25 degrees east and 55 to 70 degrees north. (If you're curious, look here: https://en.wikipedia.org/wiki/Geography_of_Sweden#Latitude_and_longitude)\n",
    "\n"
   ]
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   "source": [
    "## Exercise 4.1\n",
    "Use pyproj to determine the area extent in projection coordinate of the bounding box.\n",
    "\n",
    "Pyproj documentation: https://jswhit.github.io/pyproj/\n",
    "\n",
    "The transverse mercator projection parameters https://proj4.org/operations/projections/tmerc.html"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Exercise 4.2\n",
    "Create a pyresample AreaDefinition object using your computed parameters, with a resolution of ~1km"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Exercise 4.3\n",
    "Resample your metop data on your newly defined area definition."
   ]
  },
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   "metadata": {},
   "source": [
    "##  Saving the area\n",
    "The area definitions can be saved in yaml format. An `areas.yaml` file is provided in the satpy installation (https://github.com/pytroll/satpy/blob/feature-areas-yaml/satpy/etc/areas.yaml), but for areas you want to save, it is best to have an `areas.yaml` file in your working directory that will complete or replace the standard one. Alternatively, you can place your areas file in a directory pointed to by the `PPP_CONFIG_DIR` environment variable.\n",
    "To export the area you created, use the area's `create_areas_def` method."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Exercise 4.4\n",
    "Save the area you just defined into your own `areas.yaml` file. Resample your metop data using the saved area definition, ie by refering to it by name in the `scn.resample` call."
   ]
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