{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# EFIx_LP_1B (Langmuir probe 2Hz)\n",
    "\n",
    "> Abstract: Access to the electric field instrument langmuir probe data (2Hz) (level 1b product)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "%load_ext watermark\n",
    "%watermark -i -v -p viresclient,pandas,xarray,matplotlib"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import datetime as dt\n",
    "\n",
    "import matplotlib.pyplot as plt\n",
    "from viresclient import SwarmRequest\n",
    "\n",
    "request = SwarmRequest()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## EFIx_LP_1B product information\n",
    "\n",
    "Measurements from the Langmuir Probe (LP) of the Electric Field Instrument (EFI) at 2Hz, for each Swarm spacecraft.\n",
    "\n",
    "**Documentation:**\n",
    "- [Swarm Handbook: EFIx_LP_1B](https://swarmhandbook.earth.esa.int/catalogue/SW_EFIx_LP_1B)\n",
    "- [Product specification](https://earth.esa.int/eogateway/documents/20142/37627/swarm-level-1b-product-definition-specification.pdf)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Check what \"EFI\" data variables are available"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "request.available_collections(\"EFI\", details=False)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "request.available_measurements(\"EFI\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Fetch one day of EFI data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "request.set_collection(\"SW_OPER_EFIA_LP_1B\")\n",
    "request.set_products(\n",
    "    measurements=[\n",
    "        \"U_orbit\",\n",
    "        \"N_ion\",\n",
    "        \"dN_ion\",\n",
    "        \"T_elec\",\n",
    "        \"dT_elec\",\n",
    "        \"Vs\",\n",
    "        \"Vs_error\",\n",
    "        \"Flags_N_ion\",\n",
    "        \"Flags_T_elec\",\n",
    "        \"Flags_Vs\",\n",
    "    ]\n",
    ")\n",
    "data = request.get_between(dt.datetime(2016, 1, 1), dt.datetime(2016, 1, 2))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "data.sources"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Load and plot using pandas/matplotlib"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "df = data.as_dataframe()\n",
    "df.head()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "df.plot(y=[\"N_ion\", \"T_elec\", \"Vs\"], subplots=True, figsize=(20,5));"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "df.plot(x=\"Latitude\", y=\"N_ion\");"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Load as xarray"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "ds = data.as_xarray()\n",
    "ds"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "fig, (ax1, ax2) = plt.subplots(figsize=(10, 5), nrows=2, sharex=True)\n",
    "def subplot(_ax, da):\n",
    "    \"\"\"Plot a given DataArray on a given axes\"\"\"\n",
    "    _ax.plot(da)\n",
    "    _ax.set_ylabel(f\"{da.name} [{da.units}]\")\n",
    "for var, ax in zip((\"N_ion\", \"T_elec\"), (ax1, ax2)):\n",
    "    subplot(ax, ds[var])"
   ]
  }
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