36:null 37:["$","title",null,{"children":"Diagram of SNOMED CT historical concept associations | Ed Cheetham | Observable"}] 3d:Tae2,# Diagram of SNOMED CT historical concept associations This ${newTabLink("Sankey diagram", "https://en.wikipedia.org/wiki/Sankey_diagram")} helps to explain how SNOMED CT inactive concepts are handled (International Edition, September 2026). Starting on the left of the diagram, the majority of inactive concepts (tall first node) have an entry in the 'Concept inactivation indicator refset' (tall second node). Concepts in this refset are assigned one of several values such as 'Duplicate' or 'Ambiguous' (third column of nodes). Most inactive concepts are then assigned one or more active historical targets (fourth column) with the association name dependent on the nature of the inactivation indicator (${newTabLink("'Duplicates' have 'SAME AS' associations etc.", "https://docs.snomed.org/snomed-ct-specifications/snomed-ct-editorial-guide/readme/authoring/general-modeling/changes-to-components#concept-inactivation")}). This allows data containing inactive concepts to be more easily analysed when querying over the active release with an appropriately profiled ${newTabLink("history supplement", "https://docs.snomed.org/snomed-ct-specifications/snomed-ct-expression-constraint-language/behaviour-specification-with-examples/6.11-history-supplements")}. The neater and largely 'deterministic' inactivation patterns such as 'Duplicate' and 'Ambiguous' (where there is tight coupling between the inactivation indicator and the corresponding historical association) can be contrasted with other, more complex patterns. See, for example, the varied historical association handling of 'Outdated', 'Classification derived' and 'Nonconformance to editorial policy' inactivation indicators, as well as the wide number of inactivation indicators that make use of REPLACED BY active targets. Not all inactive concepts have active historical association targets. It is noteworthy, for example, that more than half of the 'Nonconformance to editorial policy' indicator concepts have NO historical association target (top of column five).3e:T1b72,// Copyright 2021-2023 Observable, Inc. // Released under the ISC license. // https://observablehq.com/@d3/sankey-diagram function SankeyChart({ nodes, // an iterable of node objects (typically [{id}, …]); implied by links if missing links // an iterable of link objects (typically [{source, target}, …]) }, { format = ",", // a function or format specifier for values in titles align = "justify", // convenience shorthand for nodeAlign nodeId = d => d.id, // given d in nodes, returns a unique identifier (string) nodeGroup, // given d in nodes, returns an (ordinal) value for color nodeGroups, // an array of ordinal values representing the node groups nodeLabel, // given d in (computed) nodes, text to label the associated rect nodeTitle = d => `${d.id}\n${format(d.value)}`, // given d in (computed) nodes, hover text nodeAlign = align, // Sankey node alignment strategy: left, right, justify, center nodeSort, // comparator function to order nodes nodeWidth = 15, // width of node rects nodePadding = 10, // vertical separation between adjacent nodes nodeLabelPadding = 6, // horizontal separation between node and label nodeStroke = "currentColor", // stroke around node rects nodeStrokeWidth, // width of stroke around node rects, in pixels nodeStrokeOpacity, // opacity of stroke around node rects nodeStrokeLinejoin, // line join for stroke around node rects linkSource = ({source}) => source, // given d in links, returns a node identifier string linkTarget = ({target}) => target, // given d in links, returns a node identifier string linkValue = ({value}) => value, // given d in links, returns the quantitative value linkPath = d3Sankey.sankeyLinkHorizontal(), // given d in (computed) links, returns the SVG path linkTitle = d => `${d.source.id} → ${d.target.id}\n${format(d.value)}`, // given d in (computed) links linkColor = "source-target", // source, target, source-target, or static color linkStrokeOpacity = 0.5, // link stroke opacity linkMixBlendMode = "multiply", // link blending mode colors = d3.schemeTableau10, // array of colors // colors = d3.schemeCategory10, // array of colors width = 640, // outer width, in pixels height = 400, // outer height, in pixels marginTop = 5, // top margin, in pixels marginRight = 1, // right margin, in pixels marginBottom = 5, // bottom margin, in pixels marginLeft = 1, // left margin, in pixels } = {}) { // Convert nodeAlign from a name to a function (since d3-sankey is not part of core d3). if (typeof nodeAlign !== "function") nodeAlign = { left: d3Sankey.sankeyLeft, right: d3Sankey.sankeyRight, center: d3Sankey.sankeyCenter }[nodeAlign] ?? d3Sankey.sankeyJustify; // Compute values. const LS = d3.map(links, linkSource).map(intern); const LT = d3.map(links, linkTarget).map(intern); const LV = d3.map(links, linkValue); if (nodes === undefined) nodes = Array.from(d3.union(LS, LT), id => ({id})); const N = d3.map(nodes, nodeId).map(intern); const G = nodeGroup == null ? null : d3.map(nodes, nodeGroup).map(intern); // Replace the input nodes and links with mutable objects for the simulation. nodes = d3.map(nodes, (_, i) => ({id: N[i]})); links = d3.map(links, (_, i) => ({source: LS[i], target: LT[i], value: LV[i]})); // Ignore a group-based linkColor option if no groups are specified. if (!G && ["source", "target", "source-target"].includes(linkColor)) linkColor = "currentColor"; // Compute default domains. if (G && nodeGroups === undefined) nodeGroups = G; // Construct the scales. const color = nodeGroup == null ? null : d3.scaleOrdinal(nodeGroups, colors); // Compute the Sankey layout. d3Sankey.sankey() .nodeId(({index: i}) => N[i]) .nodeAlign(nodeAlign) .nodeWidth(nodeWidth) .nodePadding(nodePadding) .nodeSort(nodeSort) .extent([[marginLeft, marginTop], [width - marginRight, height - marginBottom]]) ({nodes, links}); // Compute titles and labels using layout nodes, so as to access aggregate values. if (typeof format !== "function") format = d3.format(format); const Tl = nodeLabel === undefined ? N : nodeLabel == null ? null : d3.map(nodes, nodeLabel); const Tt = nodeTitle == null ? null : d3.map(nodes, nodeTitle); const Lt = linkTitle == null ? null : d3.map(links, linkTitle); // A unique identifier for clip paths (to avoid conflicts). const uid = `O-${Math.random().toString(16).slice(2)}`; const svg = d3.create("svg") .attr("width", width) .attr("height", height) .attr("viewBox", [0, 0, width, height]) .attr("style", "max-width: 100%; height: auto; height: intrinsic;"); const node = svg.append("g") .attr("stroke", nodeStroke) .attr("stroke-width", nodeStrokeWidth) .attr("stroke-opacity", nodeStrokeOpacity) .attr("stroke-linejoin", nodeStrokeLinejoin) .selectAll("rect") .data(nodes) .join("rect") .attr("x", d => d.x0) .attr("y", d => d.y0) .attr("height", d => d.y1 - d.y0) .attr("width", d => d.x1 - d.x0); if (G) node.attr("fill", ({index: i}) => color(G[i])); if (Tt) node.append("title").text(({index: i}) => Tt[i]); const link = svg.append("g") .attr("fill", "none") .attr("stroke-opacity", linkStrokeOpacity) .selectAll("g") .data(links) .join("g") .style("mix-blend-mode", linkMixBlendMode); if (linkColor === "source-target") link.append("linearGradient") .attr("id", d => `${uid}-link-${d.index}`) .attr("gradientUnits", "userSpaceOnUse") .attr("x1", d => d.source.x1) .attr("x2", d => d.target.x0) .call(gradient => gradient.append("stop") .attr("offset", "0%") .attr("stop-color", ({source: {index: i}}) => color(G[i]))) .call(gradient => gradient.append("stop") .attr("offset", "100%") .attr("stop-color", ({target: {index: i}}) => color(G[i]))); link.append("path") .attr("d", linkPath) .attr("stroke", linkColor === "source-target" ? ({index: i}) => `url(#${uid}-link-${i})` : linkColor === "source" ? ({source: {index: i}}) => color(G[i]) : linkColor === "target" ? ({target: {index: i}}) => color(G[i]) : linkColor) .attr("stroke-width", ({width}) => Math.max(1, width)) .call(Lt ? path => path.append("title").text(({index: i}) => Lt[i]) : () => {}); if (Tl) svg.append("g") .attr("font-family", "sans-serif") .attr("font-size", 8) .selectAll("text") .data(nodes) .join("text") .attr("x", d => d.x0 < width / 2 ? d.x1 + nodeLabelPadding : d.x0 - nodeLabelPadding) .attr("y", d => (d.y1 + d.y0) / 2) .attr("dy", "0.35em") .attr("text-anchor", d => d.x0 < width / 2 ? "start" : "end") .text(({index: i}) => Tl[i]); function intern(value) { return value !== null && typeof value === "object" ? value.valueOf() : value; } return Object.assign(svg.node(), {scales: {color}}); }3f:[{"id":"55e522acb9e1453f42cc3a88dec916517666ae0b5edcc449880722f2725f1af6106c1a3b9d5e5e3535424735efa30c7fff6123279eed1660b57367de53036c68","href":"https://static.observableusercontent.com/files/55e522acb9e1453f42cc3a88dec916517666ae0b5edcc449880722f2725f1af6106c1a3b9d5e5e3535424735efa30c7fff6123279eed1660b57367de53036c68","name":"inactivation.csv","type":"text/csv","lastModified":1789719456102,"size":1873}] 3b:{"id":"2c46c7417f9a5825","slug":"diagram-of-snomed-ct-historical-concept-associations","title":"Diagram of SNOMED CT historical concept associations","thumbnail":"b7d19c0dbfb721b9e0a42a431818e42bb4d7e1938c7252578c2e21ead7500b92","access_level":"public","create_time":"$D2026-06-23T05:09:51.971Z","update_time":"$D2026-09-21T12:00:29.960Z","view_time":null,"first_public_time":"$D2026-07-14T07:51:48.157Z","has_unpublished_edits":null,"fork":{"id":"99b2e903e7df3b0a","slug":"sankey-component","title":"Sankey diagram component","owner":{"id":"863951e3ebe4c0ae","login":"d3","name":"D3"}},"stars":0,"starred":false,"owner":{"type":"team","id":"7b0ed811d8122328","login":"echeetham","name":"Ed Cheetham","avatar_url":"https://avatars-next.observableusercontent.com/51124599fd195d575e9dc10e2344fc520a62ac4742c1008669d3d23adfc1ac95","tier":"starter_2024","bio":"","following":false},"version":919,"publish_version":919,"role":null,"authored":false,"authors":[{"type":"individual","id":"ccf792b1fa975c95","login":"echeetham","name":"Ed Cheetham","avatar_url":"https://avatars-next.observableusercontent.com/51124599fd195d575e9dc10e2344fc520a62ac4742c1008669d3d23adfc1ac95","tier":null,"bio":"","following":false}],"members":[{"type":"team","id":"7b0ed811d8122328","login":"echeetham","name":"Ed Cheetham","avatar_url":"https://avatars-next.observableusercontent.com/51124599fd195d575e9dc10e2344fc520a62ac4742c1008669d3d23adfc1ac95","tier":"starter_2024","role":"editor"},{"type":"individual","id":"ccf792b1fa975c95","login":"echeetham","name":"Ed Cheetham","avatar_url":"https://avatars-next.observableusercontent.com/51124599fd195d575e9dc10e2344fc520a62ac4742c1008669d3d23adfc1ac95","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Diagram of SNOMED CT historical concept associations","cells":[{"id":0,"value":"$3d","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":375,"value":"viewof linkColor = Inputs.select(new Map([\n [\"static\", \"#aaa\"],\n [\"source-target\", \"source-target\"],\n [\"source\", \"source\"],\n [\"target\", \"target\"],\n]), {\n value: new URLSearchParams(html``.search).get(\"color\") || \"source\",\n label: \"Link color\"\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":373,"value":"viewof nodeAlign = Inputs.select([\"left\", \"right\", \"center\", \"justify\"], {\n value: \"justify\",\n label: \"Node alignment\"\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":285,"value":"chart = SankeyChart({\n links: inactivation\n}, {\n nodeGroup: d => d.id.split(/\\W/)[0], // take first word for color\n nodeAlign, // e.g., d3.sankeyJustify; set by input above\n linkColor, // e.g., \"source\" or \"target\"; set by input above\n format: (f => d => `${f(d)} Concepts`)(d3.format(\",.1~f\")),\n width,\n height: 600\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":725,"value":"**Data imports**","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":844,"value":"const rawData = await FileAttachment(\"inactivation.csv\").csv({typed: \"auto\"});\nconst inactivation = rawData.filter(d => d.value > 0);","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":727,"value":"**Code imports etc.**","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":11,"value":"$3e","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":848,"value":"import * as d3Sankey from \"npm:d3-sankey\";","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"// d3Sankey = require.alias({\"d3-array\": d3, \"d3-shape\": d3, \"d3-sankey\": \"d3-sankey@0.12.3/dist/d3-sankey.min.js\"})(\"d3-sankey\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":784,"value":"// from https://observablehq.com/@daynex/helper-functions\nnewTabLink = (displayText, url) => {\n return `${displayText}`;\n}\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":842,"value":"**Styles**","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":802,"value":"html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":821,"value":"html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W3f","stdlib":"2"}} 3c:"$3b:body"