diff --git a/.gitignore b/.gitignore
index 93e00d56..8ed6ac8e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,5 @@ notebooks/__pycache__
 .cache
 .pytest_cache
 __pycache__
+# data file downloaded in notebooks/07.01-ipyleaflet.ipynb
+wind-global.nc
diff --git a/binder/environment.yml b/binder/environment.yml
index 89b0a0ee..526ac27e 100644
--- a/binder/environment.yml
+++ b/binder/environment.yml
@@ -25,5 +25,6 @@ dependencies:
   - voila-vuetify
   - jupyterlab=2
   - ipyvolume=0.6.0a6
+  - xarray
   - pip:
     - netcdf4
diff --git a/environment.yml b/environment.yml
index 0ad11f3b..34696f8f 100644
--- a/environment.yml
+++ b/environment.yml
@@ -27,3 +27,6 @@ dependencies:
   - jupyterlab=2
   - ipyvolume=0.6.0a6
   - nodejs=13
+  - xarray
+  - pip:
+    - netcdf4
diff --git a/notebooks/07.01-ipyleaflet.ipynb b/notebooks/07.01-ipyleaflet.ipynb
index 887382b7..2cdb62c2 100644
--- a/notebooks/07.01-ipyleaflet.ipynb
+++ b/notebooks/07.01-ipyleaflet.ipynb
@@ -451,28 +451,22 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Advanced example 1: Velocity\n",
-    "\n",
-    "*It is ok to skip this for now -- running it requires downloading a ~1MB data file.*\n",
-    "\n",
-    "This example needs an extra dependency that is not in the installation instructions and a dataset.\n",
-    "\n",
-    "You can install it with this:\n",
-    "\n",
-    "```bash\n",
-    "pip install netcdf4\n",
-    "```\n",
-    "\n",
-    "To download the data, copy and paste the code below into a new cell and run it.\n",
-    "\n",
-    "```python\n",
+    "## Advanced example 1: Velocity"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Download the data\n",
     "import requests\n",
     "\n",
     "wind_data = requests.get('https://github.com/benbovy/xvelmap/raw/master/notebooks/wind-global.nc')  \n",
     "\n",
     "with open('wind-global.nc', 'wb') as f:  \n",
-    "    f.write(wind_data.content)\n",
-    "```\n"
+    "    f.write(wind_data.content)"
    ]
   },
   {
@@ -522,7 +516,8 @@
     "                velocity_scale=0.01,\n",
     "                max_velocity=20,\n",
     "                display_options=display_options)\n",
-    "m2.add_layer(wind)"
+    "m2.add_layer(wind)\n",
+    "m2"
    ]
   },
   {
diff --git a/requirements.txt b/requirements.txt
index ef1e18d5..d02b7aef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -20,4 +20,6 @@ jupyterlab>=2
 ipyvuetify
 voila-vuetify
 sidecar
-ipyvolume==0.6.0-a.6
\ No newline at end of file
+ipyvolume==0.6.0-a.6
+xarray
+netcdf4