create_wms_template.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Generating a WMS template\n",
    "\n",
    "This Jupyter notebook can be used to generate a template using a WMS Server.\n",
    "\n",
    "**Click on the cell below and click on \"Run\" to import the necessary libraries.**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import xml.etree.ElementTree as ET\n",
    "from io import StringIO\n",
    "import requests\n",
    "from collections import OrderedDict\n",
    "import json\n",
    "from urllib.parse import urlparse, parse_qsl, urlencode, urlunparse"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "def parse_wms(xml):\n",
    "    \"\"\" Rudimentary parsing of WMS Layers from GetCapabilites Request\n",
    "        owslib.wms seems to have problems parsing some weird not relevant metadata.\n",
    "        This function aims at only parsing relevant layer metadata\n",
    "    \"\"\"\n",
    "    wms = {}\n",
    "    try:\n",
    "        it = ET.iterparse(StringIO(xml))\n",
    "        for _, el in it:\n",
    "            prefix, has_namespace, postfix = el.tag.partition('}')\n",
    "            if has_namespace:\n",
    "                el.tag = postfix\n",
    "        root = it.root\n",
    "    except:\n",
    "        raise RuntimeError(\"Could not parse XML.\")\n",
    "\n",
    "    root_tag = root.tag.rpartition(\"}\")[-1]\n",
    "    if root_tag in {'ServiceExceptionReport', 'ServiceException'}:\n",
    "        raise RuntimeError(\"WMS service exception\")\n",
    "\n",
    "    if root_tag not in {'WMT_MS_Capabilities', 'WMS_Capabilities'}:\n",
    "        raise RuntimeError(\"No Capabilities Element present: Root tag: {}\".format(root_tag))\n",
    "\n",
    "    if 'version' not in root.attrib:\n",
    "        raise RuntimeError(\"WMS version cannot be identified.\")\n",
    "    version = root.attrib['version']\n",
    "    wms['version'] = version\n",
    "\n",
    "    layers = {}\n",
    "\n",
    "    def parse_layer(element, crs=set(), styles={}):\n",
    "        new_layer = {'CRS': crs,\n",
    "                     'Styles': {}}\n",
    "        new_layer['Styles'].update(styles)\n",
    "        for tag in ['Name', 'Title', 'Abstract']:\n",
    "            e = element.find(\"./{}\".format(tag))\n",
    "            if e is not None:\n",
    "                new_layer[e.tag] = e.text\n",
    "        for tag in ['CRS', 'SRS']:\n",
    "            es = element.findall(\"./{}\".format(tag))\n",
    "            for e in es:\n",
    "                new_layer[\"CRS\"].add(e.text.upper())\n",
    "        for tag in ['Style']:\n",
    "            es = element.findall(\"./{}\".format(tag))\n",
    "            for e in es:\n",
    "                new_style = {}\n",
    "                for styletag in ['Title', 'Name']:\n",
    "                    new_style[styletag] = e.find(\"./{}\".format(styletag)).text\n",
    "                new_layer[\"Styles\"][new_style['Name']] = new_style\n",
    "\n",
    "        if 'Name' in new_layer:\n",
    "            layers[new_layer['Name']] = new_layer\n",
    "\n",
    "        for sl in element.findall(\"./Layer\"):\n",
    "            parse_layer(sl,\n",
    "                        new_layer['CRS'].copy(),\n",
    "                        new_layer['Styles'])\n",
    "\n",
    "    # Find child layers. CRS and Styles are inherited from parent\n",
    "    top_layers = root.findall(\".//Capability/Layer\")\n",
    "    for top_layer in top_layers:\n",
    "        parse_layer(top_layer)\n",
    "\n",
    "    wms['layers'] = layers\n",
    "\n",
    "    # Parse formats\n",
    "    formats = []\n",
    "    for es in root.findall(\".//Capability/Request/GetMap/Format\"):\n",
    "        formats.append(es.text)\n",
    "    wms['formats'] = formats\n",
    "    \n",
    "    return wms"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Update wms_url in the following cell. Then activate the cell and click on \"Run\"."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "wms_url = 'https://wms.zh.ch/OGDLidarZH?SERVICE=WMS&Request=GetCapabilities'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Next, activate the following cell and click on \"Run\". At the end of the cell you can then select the required properties of the service."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "scrolled": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Layers:\n",
      "0: OGDLidarZH (Digitale Höhenmodelle 2014 ZH)\n",
      "1: dtm2014hillshade (Terrainschummerung)\n",
      "2: dom2014hillshade (Oberflächenschummerung)\n",
      "3: blatteinteilung-lidar (Blatteinteilung Lidar)\n",
      "4: blatteinteilung-dtm (Digitales Terrain Modell (DTM)/Digitales Oberflächenmodell (DOM))\n",
      "5: gemeindegrenzen (Gemeindegrenzen)\n",
      "6: blatteinteilung-labels_lidar (LIDAR Beschriftung)\n",
      "7: blatteinteilung-labels_dtm (DTM/DOM Beschriftung)\n",
      " \n",
      "Select Layer: 1\n",
      " \n",
      "Image formats:\n",
      "0: image/png\n",
      "1: image/jpeg\n",
      "2: image/png; mode=8bit\n",
      "3: application/x-pdf\n",
      "4: image/svg+xml\n",
      "5: image/tiff\n",
      "6: application/vnd.google-earth.kml+xml\n",
      "7: application/vnd.google-earth.kmz\n",
      " \n",
      "Select Format: 1\n",
      " \n",
      "\n",
      "Copy the following output:\n",
      "-------------------------\n",
      "{\n",
      "    \"type\": \"Feature\",\n",
      "    \"properties\": {\n",
      "        \"name\": \"Terrainschummerung\",\n",
      "        \"type\": \"wms\",\n",
      "        \"url\": \"https://wms.zh.ch/OGDLidarZH?LAYERS=dtm2014hillshade&STYLES=&FORMAT=image/jpeg&CRS={proj}&WIDTH={width}&HEIGHT={height}&BBOX={bbox}&VERSION=1.3.0&SERVICE=WMS&REQUEST=GetMap\",\n",
      "        \"license_url\": \"\",\n",
      "        \"privacy_policy_url\": \"\",\n",
      "        \"id\": \"\",\n",
      "        \"description\": \"\",\n",
      "        \"country_code\": \"\",\n",
      "        \"best\": false,\n",
      "        \"start_date\": \"\",\n",
      "        \"end_date\": \"\",\n",
      "        \"category\": \"\",\n",
      "        \"available_projections\": [\n",
      "            \"EPSG:31297\",\n",
      "            \"EPSG:21782\",\n",
      "            \"EPSG:2056\",\n",
      "            \"EPSG:21781\",\n",
      "            \"EPSG:21780\",\n",
      "            \"EPSG:4326\",\n",
      "            \"EPSG:4258\",\n",
      "            \"EPSG:3857\"\n",
      "        ],\n",
      "        \"attribution\": {\n",
      "            \"url\": \"\",\n",
      "            \"text\": \"\",\n",
      "            \"html\": \"\",\n",
      "            \"required\": true\n",
      "        }\n",
      "    },\n",
      "    \"geometry\": \"\"\n",
      "}\n",
      "-------------------------\n"
     ]
    }
   ],
   "source": [
    "wms_args = {}\n",
    "u = urlparse(wms_url)\n",
    "url_parts = list(u)\n",
    "for k, v in parse_qsl(u.query):\n",
    "    wms_args[k.lower()] = v\n",
    "\n",
    "def get_getcapabilitie_url():\n",
    "\n",
    "    get_capabilities_args = {'service': 'WMS',\n",
    "                             'request': 'GetCapabilities'}\n",
    "    if 'version' in wms_args:\n",
    "        get_capabilities_args['version'] = wms_args['version']\n",
    "\n",
    "\n",
    "    # Some server only return capabilities when the map parameter is specified\n",
    "    if 'map' in wms_args:\n",
    "        get_capabilities_args['map'] = wms_args['map']\n",
    "\n",
    "    url_parts[4] = urlencode(list(get_capabilities_args.items()))\n",
    "    return urlunparse(url_parts)\n",
    "\n",
    "url = get_getcapabilitie_url()\n",
    "\n",
    "\n",
    "r = requests.get(url)\n",
    "xml = r.text\n",
    "wms = parse_wms(xml)\n",
    "\n",
    "print(\"Layers:\")\n",
    "layers = list(wms['layers'].keys())\n",
    "for i, layer in enumerate(layers):\n",
    "    print(\"{}: {} ({})\".format(i,\n",
    "                               layers[i],\n",
    "                               wms['layers'][layer]['Title']))\n",
    "\n",
    "print(\" \")\n",
    "selected_layer_idx = int(input(\"Select Layer: \"))\n",
    "print(\" \")\n",
    "\n",
    "assert 0 <= selected_layer_idx < len(layers)\n",
    "selected_layer = layers[selected_layer_idx]\n",
    "description = ''\n",
    "if 'Abstract' in wms['layers'][selected_layer]:\n",
    "    description = wms['layers'][selected_layer]['Abstract']\n",
    "layer_title = ''\n",
    "if 'Title' in wms['layers'][selected_layer]:\n",
    "    layer_title = wms['layers'][selected_layer]['Title']\n",
    "\n",
    "crs_options = wms['layers'][selected_layer]['CRS']\n",
    "\n",
    "styles = list(wms['layers'][selected_layer]['Styles'].keys())\n",
    "selected_style = None\n",
    "if len(styles) > 0:\n",
    "    print(\"Styles:\")\n",
    "    for i, style in enumerate(styles):\n",
    "        print(\"{}: {} ({})\".format(i, style, (wms['layers'][selected_layer]['Styles'][style]['Title'])))\n",
    "    print(\" \")\n",
    "    selected_style_idx = int(input(\"Select Style: \"))\n",
    "    print(\" \")\n",
    "\n",
    "    assert 0 <= selected_style_idx < len(styles)\n",
    "    selected_style = styles[selected_style_idx]\n",
    "else:\n",
    "    selected_style = ''\n",
    "\n",
    "print(\"Image formats:\")\n",
    "format_options = wms['formats']\n",
    "for i, format_option in enumerate(format_options):\n",
    "    print(\"{}: {}\".format(i, format_option))\n",
    "\n",
    "print(\" \")\n",
    "selected_format_idx = int(input(\"Select Format: \"))\n",
    "print(\" \")\n",
    "assert 0 <= selected_format_idx < len(format_options)\n",
    "selected_format = format_options[selected_format_idx]\n",
    "\n",
    "wms_paramters = {}\n",
    "wms_paramters['LAYERS'] = selected_layer\n",
    "if selected_style is not None:\n",
    "    wms_paramters['STYLES'] = selected_style\n",
    "wms_paramters['FORMAT'] = selected_format\n",
    "wms_paramters['CRS'] = '{proj}'\n",
    "wms_paramters['WIDTH'] = '{width}'\n",
    "wms_paramters['HEIGHT'] = '{height}'\n",
    "wms_paramters['BBOX'] = '{bbox}'\n",
    "wms_paramters['VERSION'] = wms['version']\n",
    "wms_paramters['SERVICE'] = 'WMS'\n",
    "wms_paramters['REQUEST'] = 'GetMap'\n",
    "\n",
    "baseurl = wms_url.split(\"?\")[0]\n",
    "service_url = baseurl + \"?\" + \"&\".join([\"{}={}\".format(key, value) for key, value in wms_paramters.items()])\n",
    "\n",
    "result = OrderedDict()\n",
    "result['type'] = 'Feature'\n",
    "result['properties'] = OrderedDict()\n",
    "result['properties']['name'] = layer_title\n",
    "result['properties']['type'] = 'wms'\n",
    "result['properties']['url'] = service_url\n",
    "result['properties']['license_url'] = ''\n",
    "result['properties']['privacy_policy_url'] = ''\n",
    "result['properties']['id'] = ''\n",
    "result['properties']['description'] = description\n",
    "result['properties']['country_code'] = ''\n",
    "result['properties']['best'] = False\n",
    "result['properties']['start_date'] = ''\n",
    "result['properties']['end_date'] = ''\n",
    "result['properties']['category'] = ''\n",
    "result['properties']['available_projections'] = list(crs_options)\n",
    "result['properties']['attribution'] = {'url': '',\n",
    "                                       'text': '',\n",
    "                                       'html': '',\n",
    "                                       'required': True}\n",
    "result['geometry'] = ''\n",
    "\n",
    "\n",
    "print(\"\")\n",
    "print(\"Copy the following output:\")\n",
    "print(\"-------------------------\")\n",
    "print(json.dumps(result,\n",
    "                 indent=4,\n",
    "                 sort_keys=False))\n",
    "print(\"-------------------------\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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