Testing ipyleaflt map.fit_bounds(), setting zoom level too low

fit_bounds.ipynb

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   "source": [
    "# Check map zoom level after fit_bounds()"
   ]
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   "cell_type": "markdown",
   "id": "852cf6e7-8330-4070-bf91-0a644cc5ec8a",
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   "source": [
    "## Load data"
   ]
  },
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   "execution_count": null,
   "id": "e65753b6-fee7-42db-8d5e-f9924abd5534",
   "metadata": {},
   "outputs": [],
   "source": [
    "import geojson\n",
    "import requests"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "a769297e-e74a-4dfc-926b-c6c0e079f765",
   "metadata": {},
   "outputs": [],
   "source": [
    "def bounds(feat):\n",
    "    bounds = geojson.utils.coords(feat)\n",
    "    lon, lat = next(bounds)\n",
    "    east, west, north, south = lon, lon, lat, lat\n",
    "    for lon, lat in bounds:\n",
    "        east = lon if lon > east else east\n",
    "        west = lon if lon < west else west\n",
    "        north = lat if lat > north else north\n",
    "        south = lat if lat < south else south\n",
    "    return [[south, west], [north, east]]\n",
    "\n",
    "countries = requests.get(\n",
    "    \"https://raw.githubusercontent.com/johan/world.geo.json\"\n",
    "    \"/master/countries.geo.json\"\n",
    ").json()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "7b117cb2-163f-4554-a8cf-8ae64de39126",
   "metadata": {
    "tags": []
   },
   "source": [
    "## Simple, zoom level too low"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "65e5a908-9e2f-42bc-a26f-716c8c1593fc",
   "metadata": {},
   "outputs": [],
   "source": [
    "from ipyleaflet import basemaps, GeoJSON, Map\n",
    "\n",
    "m = Map(basemap=basemaps.CartoDB.Positron)\n",
    "feat = countries[\"features\"][0]\n",
    "m += GeoJSON(data=feat)\n",
    "bnds = bounds(feat)\n",
    "print(feat[\"properties\"][\"name\"])\n",
    "m.fit_bounds(bnds)\n",
    "m"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0cafe5a1-fa7b-438d-8240-2c03a932371b",
   "metadata": {
    "tags": []
   },
   "source": [
    "## interact(), zoom level too low"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "02fd9c2a-48f5-459b-a051-d1a38aeb6209",
   "metadata": {},
   "outputs": [],
   "source": [
    "from ipyleaflet import basemaps, GeoJSON, Map\n",
    "from ipywidgets import interact\n",
    "\n",
    "@interact\n",
    "def run(index=(0, len(countries[\"features\"])-1)):\n",
    "    m = Map(basemap=basemaps.CartoDB.Positron)\n",
    "    feat = countries[\"features\"][index]\n",
    "    m += GeoJSON(data=feat)\n",
    "    bnds = bounds(feat)\n",
    "    print(feat[\"properties\"][\"name\"])\n",
    "    m.fit_bounds(bnds)\n",
    "    return m"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c8b58982-a97a-433c-8acf-de4d49539c9b",
   "metadata": {
    "tags": []
   },
   "source": [
    "## Play widget, zoom level ok"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "1cb6b49f-68b8-483b-a403-8de5039ecb55",
   "metadata": {},
   "outputs": [],
   "source": [
    "from ipyleaflet import basemaps, GeoJSON, Map, WidgetControl\n",
    "from ipywidgets import HBox, Play, Text\n",
    "\n",
    "def changed(event):\n",
    "    global m, prev_gj\n",
    "    if event[\"name\"] != \"value\":\n",
    "        return\n",
    "    if prev_gj:\n",
    "        m -= prev_gj\n",
    "    i = event[\"owner\"].value\n",
    "    feat = countries[\"features\"][i]\n",
    "    cc_name = feat[\"properties\"][\"name\"]\n",
    "    tx.value = f\"{i}: {cc_name}\"\n",
    "    gj = GeoJSON(data=feat)\n",
    "    m += gj\n",
    "    prev_gj = gj\n",
    "    m.fit_bounds(bounds(feat))\n",
    "\n",
    "prev_gj = None\n",
    "p = Play(min=0, max=len(countries[\"features\"])-1, interval=1000)\n",
    "p.observe(changed)\n",
    "tx = Text()\n",
    "w = HBox([p, tx])\n",
    "m = Map(zoom=1, basemap=basemaps.CartoDB.Positron)\n",
    "m += WidgetControl(widget=w, position=\"bottomleft\", transparent_bg=True)\n",
    "m"
   ]
  }
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