Emissions: ${d.emissions} kg/hr Source: ${Array.from(d.sources.values()).join(", ")}

2e:null 2f:["$","title",null,{"children":"California’s Methane ‘Super Emitters’ | Jeremy Ashkenas | Observable"}] 34:T58e,map = svg``35:[{"id":"a7e7a8772519e652a911adef8a025e4b2632de184746018c728ec69264857c8ccfa21a06179289d6596dc293b07e066e094440e471817db6a2d1ac9561b7017d","href":"https://static.observableusercontent.com/files/a7e7a8772519e652a911adef8a025e4b2632de184746018c728ec69264857c8ccfa21a06179289d6596dc293b07e066e094440e471817db6a2d1ac9561b7017d","name":"Plume_list_20191031 (1).csv","type":"text/csv","lastModified":1573168723443.401,"size":132697}] 32:{"id":"666ba7701e02a4c3","slug":"californias-methane-super-emitters","title":"California’s Methane ‘Super Emitters’","thumbnail":"6fa17106ff62a8de4b902bc0a279aaaaadb8544a2b73d8d80adb46813add38e1","access_level":"public","create_time":"$D2019-11-07T23:13:53.031Z","update_time":"$D2019-11-09T00:22:09.628Z","view_time":null,"first_public_time":"$D2019-11-07T23:57:29.020Z","has_unpublished_edits":null,"fork":false,"stars":10,"starred":false,"owner":{"type":"team","id":"172cc08ef8a18a4b","login":"jashkenas","name":"Jeremy Ashkenas","avatar_url":"https://avatars-next.observableusercontent.com/fa1903f8171d4621ef49de28e0ff1fb965960ec87df175d8b543c4b09508b45b","tier":"starter_2024"},"version":350,"publish_version":350,"role":null,"authored":false,"authors":[{"type":"individual","id":"783616ba9fb55f5d","login":"jashkenas","name":"Jeremy Ashkenas","avatar_url":"https://avatars-next.observableusercontent.com/fa1903f8171d4621ef49de28e0ff1fb965960ec87df175d8b543c4b09508b45b","tier":null}],"members":[{"type":"individual","id":"783616ba9fb55f5d","login":"jashkenas","name":"Jeremy Ashkenas","avatar_url":"https://avatars-next.observableusercontent.com/fa1903f8171d4621ef49de28e0ff1fb965960ec87df175d8b543c4b09508b45b","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":4,"collection":null,"type":"notebook","body":{"title":"California’s Methane ‘Super Emitters’","cells":[{"id":0,"value":"md`# California’s Methane ‘Super Emitters’\n*As measured by flights done by NASA’s Earth Science Division*\n\nIn a [recent report](https://www.jpl.nasa.gov/news/news.php?feature=7535), NASA scientists flew methane detecting instruments above nearly 300,000 potential methane emissions sources in California, over two years. They determined that there are just 30 landfills in the state that account for 40% of the total emissions detected during the survey.\n\n*Source: [methane.jpl.nasa.gov](https://methane.jpl.nasa.gov/)*`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":77,"value":"viewof filter = radio({\n description:\n 'NASA found that just ten percent of sources emitted a majority of the leaked methane',\n options: [\n { label: 'All emitters', value: 'all' },\n { label: 'Top 10%, aka the ‘Super Emitters’', value: 'top' }\n ],\n value: 'all'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":19,"value":"css = html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":99,"value":"filtered = filter === \"all\"\n ? nested\n : nested.filter((d, i) => i < Math.round(nested.length / 10))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":129,"value":"nested = d3\n .nest()\n .key(function(d) {\n return `${Math.round(\n d.longitude * 10\n )}, ${Math.round(d.latitude * 10)}, ${d.classification}`;\n })\n .rollup(function(sources) {\n return {\n latitude: d3.mean(sources, d => d.latitude),\n longitude: d3.mean(sources, d => d.longitude),\n emissions: d3.sum(sources, d => d.emissions),\n sources: new Set(sources.map(d => d.source)),\n classification: sources[0].classification\n };\n })\n .entries(data)\n .map(d => d.value)\n .sort((a, b) => b.emissions - a.emissions)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":31,"value":"data = raw.map(d => ({\n latitude: +d[\"Plume latitude (deg)\"],\n longitude: +d[\"Plume longitude (deg)\"],\n source: d[\"Source type (best estimate)\"],\n classification: classify(d[\"Source type (best estimate)\"]),\n emissions: +d[\"Qplume (kg/hr): Plume emissions\"]\n}))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":28,"value":"raw = d3.csv(await FileAttachment(\"Plume_list_20191031 (1).csv\").url())","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":249,"value":"function classify(source) {\n if (/^(oil|gas|refinery)/.test(source)) return \"oil/gas\";\n if (/^dairy/.test(source)) return \"dairy\";\n if (/^wastewater/.test(source)) return \"water treatment\";\n if (/^power/.test(source)) return \"power\";\n return \"landfill\";\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":264,"value":"colorMap = ({\n \"water treatment\": colors[0],\n power: colors[3],\n \"oil/gas\": colors[2],\n dairy: colors[1],\n landfill: colors[4]\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":258,"value":"colors = [\"#505a6b\", \"#7ba8de\", \"#e5b64f\", \"#499135\", \"#a44f4c\"]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":207,"value":"height = width","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":34,"value":"radius = d3.scaleSqrt(\n [0, d3.quantile(nested.map(d => d.emissions).sort(d3.ascending), 0.985)],\n [0, Math.min(35, Math.round(width / 20))]\n)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":16,"value":"path = d3.geoPath().projection(projection)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"projection = d3\n .geoMercator()\n .center([-118.75, 37.5])\n .scale(1)\n .fitSize([width - 20, height - 20], state)\n .translate([width / 2, width / 2])","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":78,"value":"cities = [\n {\n name: 'Los Angeles',\n coordinates: [-118.2437, 33.95]\n },\n {\n name: \"Oakland\",\n coordinates: [-122.21, 37.81]\n },\n { name: \"Modesto\", coordinates: [-120.996, 37.639] },\n {\n name: \"Redding\",\n coordinates: [-122.3917, 40.5865]\n },\n {\n name: \"Sacramento\",\n coordinates: [-121.4944, 38.5816]\n },\n { name: \"Bakersfield\", coordinates: [-119.018, 35.373] },\n {\n name: \"San Diego\",\n coordinates: [-117.1611, 32.7157],\n x: \"-9\",\n anchor: \"end\"\n },\n {\n name: \"Fresno\",\n coordinates: [-119.7871, 36.7378]\n }\n]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":8,"value":"state = {\n const url =\n \"https://gist.githubusercontent.com/palewire/e001c971f2cab1664168658caa7536da/raw/state.json\";\n const r = await d3.json(url);\n return topojson.feature(r, r.objects[\"state\"]).features[0];\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":4,"value":"d3 = require(\"d3@5\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"topojson = require(\"topojson-client@3\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":73,"value":"import { radio } from \"@jashkenas/inputs\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1","titling":"auto"}} 33:"$32:body"