31:T423,md`# Berlin's Stolpersteine

Sources: [Wikidata](https://www.wikidata.org/wiki/Q314003) and [solpersteine-berlin](https://www.stolpersteine-berlin.de/en) > "A Stolperstein (pronounced [ˈʃtɔlpɐˌʃtaɪn]; literally "stumbling stone", metaphorically a "stumbling block") is a sett-size, ten-centimetre (3.9 in) concrete cube bearing a brass plate inscribed with the name and life dates of victims of Nazi extermination or persecution." > "Project created by Gunter Demnig for honoring victims of National Socialism" > "Today, Stolpersteine are being realized for Jews, Sinti and Roma, people from the political or religious resistance, victims of the "euthanasia" murders, homosexuals, Jehovahs Witnesses and for people who were persecuted for being declared to be „asocial“." [(Wikipedia)](https://en.wikipedia.org/wiki/Stolperstein)`32:T535,md` \`\`\`js wikidata_response = await fetch( "https://query.wikidata.org/sparql?query=%23defaultView%3AMap%0ASELECT%20%3FStolperstein%20%3FStolpersteinLabel%20%3Fgeographische_Koordinaten%20WHERE%20%7B%0A%20%20SERVICE%20wikibase%3Alabel%20%7B%20bd%3AserviceParam%20wikibase%3Alanguage%20%22en%2Cen%22.%20%7D%0A%20%20%3FStolperstein%20wdt%3AP31%20wd%3AQ26703203.%0A%20%20OPTIONAL%20%7B%20%3FStolperstein%20wdt%3AP625%20%3Fgeographische_Koordinaten.%20%7D%0A%7D", { credentials: "include", headers: { "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:82.0) Gecko/20100101 Firefox/82.0", Accept: "application/sparql-results+json", "Accept-Language": "en-US,en;q=0.5", "X-Requested-With": "XMLHttpRequest", "Sec-GPC": "1" }, referrer: "https://query.wikidata.org/embed.html", method: "GET", mode: "cors" } ) wikidata_body = await wikidata_response.json() wikidata_data = wikidata_body.results.bindings .filter(e => e.geographische_Koordinaten) .map(e => { return { label: e.StolpersteinLabel.value.replace( "Stolperstein dedicated to ", "" ), geo: e.geographische_Koordinaten.value .replace("Point(", "") .replace(")", "") .split(" ") .map(d => parseFloat(d)) }; }) \`\`\` `33:[{"id":"50cf93d56f08f8da05da95c6eec464b047f570da893a9d047b46f4cbb298ef792acaaf030a87264a7351984ac0d567f0014c9cf61996292080644108a902ba61","href":"https://static.observableusercontent.com/files/50cf93d56f08f8da05da95c6eec464b047f570da893a9d047b46f4cbb298ef792acaaf030a87264a7351984ac0d567f0014c9cf61996292080644108a902ba61","name":"all_data.json","type":"application/json","lastModified":1605297246387.631,"size":923645},{"id":"a98ed5cd8ec542c30577e38a63c2ebe57a4d6bdc05a52b04248c3764b4cf6cfa10b63ad49c409f6cfcd1db5fd9ace7a1d86842f512ac33dd468d14fa5a7b0872","href":"https://static.observableusercontent.com/files/a98ed5cd8ec542c30577e38a63c2ebe57a4d6bdc05a52b04248c3764b4cf6cfa10b63ad49c409f6cfcd1db5fd9ace7a1d86842f512ac33dd468d14fa5a7b0872","name":"wikidata_body.json","type":"application/json","lastModified":1605296661538.355,"size":4631602},{"id":"4f071cd3146be79b9c6a2a05986d3bbd36e7501fc36ccb3fe8ad9bfef66356486c85341d8efb1e56f2f1206cc1eb383f771caaa9520097cf2b57960b1c369eaf","href":"https://static.observableusercontent.com/files/4f071cd3146be79b9c6a2a05986d3bbd36e7501fc36ccb3fe8ad9bfef66356486c85341d8efb1e56f2f1206cc1eb383f771caaa9520097cf2b57960b1c369eaf","name":"wikidata_body@1.json","type":"application/json","lastModified":1766051621091.237,"size":23770486},{"id":"6e57d555e917d88f83bf2e4546695ae80efd0c7a28d26cc3abda5cc070e26cfa31fcf888f0f0fc5a3620c60f12f2ad74e56f751f3e38009d7471704824d5d10a","href":"https://static.observableusercontent.com/files/6e57d555e917d88f83bf2e4546695ae80efd0c7a28d26cc3abda5cc070e26cfa31fcf888f0f0fc5a3620c60f12f2ad74e56f751f3e38009d7471704824d5d10a","name":"all_data@1.json","type":"application/json","lastModified":1766051580607.804,"size":1759371}] 2f:{"title":"Berlin's Stolpersteine","cells":[{"id":244,"value":"$31","pinned":false,"hidden":false,"mode":"ojs"},{"id":480,"value":"md`We compare two public records of the location and number of Berlin's Stolpersteine: the Wikidata database, and another referenced in the daten.berlin.de catalogue, is the dataset produced by stolpersteine-berlin.de – which describes itself as \"(a) liaison office between the artist Gunter Demnig together with his team and the local Stolperstein-groups.\"`","pinned":false,"hidden":false,"mode":"ojs"},{"id":402,"value":"md`## How datasets compare\n There are now **${wikidata.filter(filterInBounds).length.toLocaleString()} Wikidata records** in Berlin—\n more than the **${berlindata_file.length.toLocaleString()} records** from stolpersteine-berlin.de.\n The Wikidata coverage has dramatically improved since this notebook was first created.\n\n🔹 Stolpersteine-berlin dataset 🔸 Wikidata reference\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":170,"value":"maps = html`

`","pinned":false,"hidden":false,"mode":"ojs"},{"id":0,"value":"md`# Stolpersteine across Europe\nThe Wikidata dataset has however the merit of spanning not only all of Germany, but also all of Europe.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":86,"value":"viz = {\n const svg = d3\n .create(\"svg\")\n .attr('id', 'svg')\n .attr('width', width)\n .attr('height', 500);\n\n const projection = d3\n .geoMercator()\n .center([17, 58])\n .scale(450)\n .rotate([0, 0]);\n\n const path = d3.geoPath().projection(projection);\n\n svg\n .selectAll(\"path\")\n .data(topojson.feature(world, world.objects.countries).features)\n .enter()\n .append(\"path\")\n .attr(\"d\", path)\n .style('fill', '#eee')\n .style('stroke', '#fff');\n\n svg\n .selectAll('circle')\n .data(wikidata)\n .enter()\n .append('circle')\n .attr('r', 2)\n .attr(\n 'transform',\n d => `translate(${projection([d.geo[0], d.geo[1]]).join(\",\")})`\n )\n .style('fill', '#FFDC00')\n .style('stroke', '#FFDC00');\n\n return svg.node();\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":361,"value":"md`## Data sources\nBelow is a how-to things would work in Observable land were it not for CORS. We're actually loading JSON representations of what the following code blocks do instead of polling for live data. \nTwo reasons for this:\n\n* This notebook will keep running even if Wikidata change something in their API or if the other provider goes down ;\n* Non-dev readers won't have to fiddle with their enable CORS button to see the notebook run.\n\nThe Wikidata data is available through a Sparql endpoint and seems to prefer proper headers and CORS on.\n\nWe exclude **${wikidata_file.results.bindings.length -\n wikidata.length}** items that do not contain geo coordinates 😕.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":21,"value":"$32","pinned":false,"hidden":false,"mode":"ojs"},{"id":389,"value":"md` Our second data source, the stolpersteine-berlin.de's database, now provides a JSON API with pre-geocoded coordinates for all 10,000+ Stolpersteine. The old XML endpoint used in the original version of this notebook no longer exists.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":613,"value":"md`\n\\`\\`\\`js\n berlin_response = await fetch(\n \"https://www.stolpersteine-berlin.de/en/api/json/stolpersteine.json\"\n )\n berlin_json = await berlin_response.json()\n berlindata_file = berlin_json.data.map(e => ({\n lat: parseFloat(e.geo__lat),\n lon: parseFloat(e.geo__lng),\n label: e.popup_title, e.first_name, e.last_name\n })\n\\`\\`\\`\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":569,"value":"md`## Load files instead of live resources...\nWe load static JSON files rather than polling live APIs. This ensures the notebook keeps running even if\n upstream APIs change (as happened with the original XML endpoint). The stolpersteine-berlin.de JSON API\n now works without CORS restrictions, but we keep local copies for stability.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":570,"value":"wikidata_file = FileAttachment(\"wikidata_body@1.json\").json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":575,"value":"wikidata = wikidata_file.results.bindings\n .filter(e => e.geographische_Koordinaten)\n .map(e => {\n return {\n label: e.StolpersteinLabel.value.replace(\n \"Stolperstein dedicated to \",\n \"\"\n ),\n geo: e.geographische_Koordinaten.value\n .replace(\"Point(\", \"\")\n .replace(\")\", \"\")\n .split(\" \")\n .map(d => parseFloat(d))\n };\n })","pinned":false,"hidden":false,"mode":"ojs"},{"id":609,"value":"berlindata_file = FileAttachment(\"all_data@1.json\").json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":165,"value":"citymap = {\n const wikimap = L.map(\"wiki\", { preferCanvas: true }).setView(\n [52.51, 13.4],\n 11\n );\n L.tileLayer(\n `https://{s}.basemaps.cartocdn.com/rastertiles/voyager_labels_under/{z}/{x}/{y}@2x.png`,\n {\n attribution:\n '© OpenStreetMap contributors © CARTO',\n subdomains: 'abcd',\n maxZoom: 19\n }\n ).addTo(wikimap);\n\n for (let i = 0; i < wikidata.length; i++) {\n const reversed = wikidata[i].geo.slice().reverse();\n\n L.circle(reversed, {\n radius: 3,\n color: '#FF851B',\n opacity: 0.8,\n fillColor: '#FF851B'\n }).addTo(wikimap);\n }\n\n // Check out what happens if you remove/comment the next next line, then rerun the cell -- twice.\n invalidation.then(() => wikimap.remove());\n return wikimap;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":457,"value":"berlinmap = {\n const wikimap = L.map(\"berlin\", { preferCanvas: true }).setView(\n [52.51, 13.4],\n 11\n );\n L.tileLayer(\n `https://{s}.basemaps.cartocdn.com/rastertiles/voyager_labels_under/{z}/{x}/{y}@2x.png`,\n {\n attribution:\n '© OpenStreetMap contributors © CARTO',\n subdomains: 'abcd',\n maxZoom: 19\n }\n ).addTo(wikimap);\n\n for (let i = 0; i < berlindata_file.length; i++) {\n const latlon = [berlindata_file[i].lat, berlindata_file[i].lon];\n L.circle(latlon, {\n radius: 5,\n color: '#0074D9',\n opacity: 0.8,\n fillColor: '#0074D9'\n }).addTo(wikimap);\n }\n\n // Check out what happens if you remove/comment the next next line, then rerun the cell -- twice.\n invalidation.then(() => wikimap.remove());\n return wikimap;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":506,"value":"filterInBounds = arr => {\n if (\n arr.geo[0] > 12.91 &&\n arr.geo[0] < 13.90 &&\n arr.geo[1] > 52.35 &&\n arr.geo[1] < 52.67\n ) {\n return arr;\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":72,"value":"xScale = d3\n .scaleLinear()\n .domain(d3.extent(wikidata.map(e => e.geo).map(e => e[0])))\n .range([0, width])","pinned":false,"hidden":false,"mode":"ojs"},{"id":81,"value":"yScale = d3\n .scaleLinear()\n .domain(d3.extent(wikidata.map(e => e.geo).map(e => e[1])))\n .range([500, 0])","pinned":false,"hidden":false,"mode":"ojs"},{"id":108,"value":"world = d3.json(\n 'https://gist.githubusercontent.com/olemi/d4fb825df71c2939405e0017e360cd73/raw/d6f9f0e9e8bd33183454250bd8b808953869edd2/world-110m2.json'\n)","pinned":false,"hidden":false,"mode":"ojs"},{"id":627,"value":"L = require(\"leaflet\");\n \n","pinned":false,"hidden":false,"mode":"ojs"},{"id":633,"value":"html``","pinned":false,"hidden":false,"mode":"ojs"},{"id":106,"value":"topojson = require(\"topojson-client@3\", \"topojson-simplify\", \"topojson-server\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":74,"value":"d3 = require('d3@5')","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W33","stdlib":"1","titling":"auto"}