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 "cells": [
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Load Kerchunked dataset with Xarray\n",
    "\n"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Overview\n",
    "   \n",
    "Within this notebook, we will cover:\n",
    "\n",
    "1. How to load a Kerchunk pre-generated reference file into Xarray as if it were a Zarr store.\n",
    "\n",
    "## Prerequisites\n",
    "| Concepts | Importance | Notes |\n",
    "| --- | --- | --- |\n",
    "| [Kerchunk Basics](../foundations/kerchunk_basics) | Required | Core |\n",
    "| [Xarray Tutorial](https://tutorial.xarray.dev/intro.html) | Required | Core |\n",
    "\n",
    "- **Time to learn**: 45 minutes\n",
    "---"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Opening Reference Dataset with Fsspec and Xarray\n",
    "One way of using our reference dataset is opening it with `Xarray`. To do this, we will create an `fsspec` filesystem and pass it to `Xarray`. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# create an fsspec reference filesystem from the Kerchunk output\n",
    "import fsspec\n",
    "import xarray as xr\n",
    "import kerchunk\n",
    "\n",
    "fs = fsspec.filesystem(\n",
    "    \"reference\",\n",
    "    fo=\"references/ARG_combined.json\",\n",
    "    remote_protocol=\"s3\",\n",
    "    skip_instance_cache=True,\n",
    ")\n",
    "m = fs.get_mapper(\"\")\n",
    "ds = xr.open_dataset(m, engine=\"zarr\")"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Opening Reference Dataset with Xarray and the `Kerchunk` Engine\n",
    "As of writing, the latest version of Kerchunk supports opening an reference dataset with Xarray without specifically creating an fsspec filesystem.  This is the same behavior as the example above, just a few less lines of code. \n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "storage_options = {\n",
    "    \"remote_protocol\": \"s3\",\n",
    "    \"skip_instance_cache\": True,\n",
    "}  # options passed to fsspec\n",
    "open_dataset_options = {\"chunks\": {}}  # opens passed to xarray\n",
    "\n",
    "ds = xr.open_dataset(\n",
    "    \"references/ARG_combined.json\",\n",
    "    engine=\"kerchunk\",\n",
    "    storage_options=storage_options,\n",
    "    open_dataset_options=open_dataset_options,\n",
    ")"
   ]
  }
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