diff --git a/examples/CRS.ipynb b/examples/CRS.ipynb
index 3058405..dd192f6 100644
--- a/examples/CRS.ipynb
+++ b/examples/CRS.ipynb
@@ -2,7 +2,6 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "id": "9d992ac4-7bef-4322-ae33-5936e48a1fbf",
    "metadata": {},
    "source": [
     "# CRS"
@@ -10,7 +9,6 @@
   },
   {
    "cell_type": "markdown",
-   "id": "892ddf5e-b164-4630-991b-6783dceca46f",
    "metadata": {},
    "source": [
     "Choosing a Coordinate Reference System (CRS) when creating a `MizarMap` defines the context of the map: a planet or a sky view.\n",
@@ -21,7 +19,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "6641d263-acd2-4b61-93fb-41cb35c7dd46",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -31,7 +28,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "dee685e6-c155-49d5-b591-738bef832c04",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -41,7 +37,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "6ad296ed-d4b4-43f1-95e4-f0a32c648fcc",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -51,7 +46,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "8c2690f0-dc71-4d44-a0f3-b12f616c789f",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -60,7 +54,6 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d9f41afe-5b25-48ee-aeb6-6e8f7191ee98",
    "metadata": {},
    "source": [
     "A `MizarMap` is created by defining its `crs` parameter (`CRS.WGS84`, planet Earth by default). Its `context` attribute (read-only) is set to either `'Planet'` or `'Sky'` given the prodived CRS."
@@ -68,7 +61,6 @@
   },
   {
    "cell_type": "markdown",
-   "id": "febc91f3-03c9-4eaf-a4b4-8461dda22b2f",
    "metadata": {},
    "source": [
     "## Planet"
@@ -77,7 +69,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "c78bd345-9732-46be-8914-f9929e79abe3",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -90,7 +81,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "c015fd30-2cf3-465e-b5fc-71cbe4879d97",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -103,7 +93,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "11f24e96-a4be-4b64-b68a-6643d8a00677",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -112,7 +101,6 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2eaa9ca8-8368-4b88-ad13-1c20a8bfd9f2",
    "metadata": {},
    "source": [
     "# Sky"
@@ -121,7 +109,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "b17804da-e450-45c6-ba69-10894ef10dd2",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -134,7 +121,6 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "b441ad63-ef9d-4be6-9277-d2f1215365db",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -158,7 +144,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.13"
+   "version": "3.8.10"
   },
   "widgets": {
    "application/vnd.jupyter.widget-state+json": {
diff --git a/examples/Intro.ipynb b/examples/Intro.ipynb
index 43fff1a..bd0ba20 100644
--- a/examples/Intro.ipynb
+++ b/examples/Intro.ipynb
@@ -9,24 +9,9 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "application/vnd.jupyter.widget-view+json": {
-       "model_id": "ac667fe212f549aa83f465b627266948",
-       "version_major": 2,
-       "version_minor": 0
-      },
-      "text/plain": [
-       "MizarMap(center=(0.0, 0.0), layers=(WMSLayer(layers='BlueMarble', url='https://regards-pp.cnes.fr/api/v1/hysop…"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "import json\n",
     "\n",
@@ -51,7 +36,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -61,7 +46,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -75,24 +60,9 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "application/vnd.jupyter.widget-view+json": {
-       "model_id": "57747f1b8c7a442293f58ee94b2c8a5b",
-       "version_major": 2,
-       "version_minor": 0
-      },
-      "text/plain": [
-       "MizarMap(center=(0.0, 0.0), crs='Equatorial', layers=(HipsLayer(url='http://alasky.unistra.fr/DSS/DSSColor'),)…"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "# A 3D Sky view can also be created\n",
     "sky = MizarMap(crs=CRS.Equatorial)\n",
@@ -104,13 +74,6 @@
     "# Display the Sky and the Hips layer\n",
     "sky"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
@@ -129,7 +92,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.5"
+   "version": "3.8.10"
   },
   "widgets": {
    "application/vnd.jupyter.widget-state+json": {
diff --git a/examples/WMS.ipynb b/examples/WMS.ipynb
index 4a86c03..48ffafd 100644
--- a/examples/WMS.ipynb
+++ b/examples/WMS.ipynb
@@ -9,7 +9,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -25,26 +25,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "metadata": {
     "tags": []
    },
-   "outputs": [
-    {
-     "data": {
-      "application/vnd.jupyter.widget-view+json": {
-       "model_id": "adac32387f9746198c2c4d643be6fa8e",
-       "version_major": 2,
-       "version_minor": 0
-      },
-      "text/plain": [
-       "MizarMap(center=(0.0, 0.0), layers=(WMSLayer(layers='viking', url='http://idoc-wmsmars.ias.u-psud.fr/cgi-bin/m…"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "mars = MizarMap(crs=CRS.WGS84)\n",
     "wms = WMSLayer(\n",
@@ -65,7 +50,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -81,7 +66,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -94,13 +79,6 @@
     ")\n",
     "mars.add_layer(themis)"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
@@ -119,7 +97,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.5"
+   "version": "3.8.10"
   },
   "widgets": {
    "application/vnd.jupyter.widget-state+json": {