2b:null 2c:["$","title",null,{"children":"Sisi Introduction to D3 Course: Lesson 3 | 🪦 dv develop 2026 spring | Observable"}] 31:T437,chart = { const width = 900; const height = 300; const marginTop = 25; const marginRight = 20; const marginBottom = 35; const marginLeft = 40; const x = d3 .scaleUtc() .domain(d3.extent(appleStockData, (d) => d.Date)) .nice() .range([0, width]); const y = d3 .scaleLinear() .domain(d3.extent(appleStockData, (d) => d.Close)) .nice() .range([height, 0]); const line = d3 .line() .x(d => x(d.Date)) .y(d => y(d.Close)); const svg = d3 .create("svg") .attr("width", width + marginLeft + marginRight) .attr("height", height + marginTop + marginBottom); const g = svg .append("g") .attr("transform", `translate(${marginLeft}, ${marginTop})`); g.append("g") .attr("transform", `translate(0,${height})`) .call(d3.axisBottom(x).ticks(width / 80)); g.append("g").call(d3.axisLeft(y)); g.append("g") .append("path") .datum(appleStockData) .attr("d", line) .style("fill", "none") .style("stroke", "#000") .style("stroke-width", 1.5); return svg.node(); }32:T4db,{ const width = 900; const height = 300; const marginTop = 25; const marginRight = 20; const marginBottom = 35; const marginLeft = 40; const x = d3 .scaleUtc() .domain(d3.extent(appleStockData, (d) => d.Date)) .nice() .range([0, width]); const bandScale = d3.scaleBand() .domain(appleStockData.map((d) => d.Date)) .range([0, width]) .padding(0.1); const y = d3 .scaleLinear() .domain(d3.extent(appleStockData, (d) => d.Close)) .nice() .range([height, 0]); const svg = d3 .create("svg") .attr("width", width + marginLeft + marginRight) .attr("height", height + marginTop + marginBottom); const g = svg .append("g") .attr("transform", `translate(${marginLeft}, ${marginTop})`); g.append("g") .attr("transform", `translate(0,${height})`) .call(d3.axisBottom(x).ticks(width / 80)); g.append("g").call(d3.axisLeft(y)); g.append("g") .attr("fill", "steelblue") .selectAll("rect") .data(appleStockData) .join("rect") .attr("x", (d) => x(d.Date)) .attr("y", (d) => y(d.Close)) .attr("width", bandScale.bandwidth()) .style("opacity", 0.8) .attr("height", (d) => height - y(d.Close)); return svg.node(); }33:T6f0,{ const width = 900; const height = 300; const marginTop = 25; const marginRight = 20; const marginBottom = 35; const marginLeft = 100; // Generate the stacked data array const series = stackLayout(populationData); // 1. X Scale: Band scale for states const x = d3.scaleBand() .domain(populationData.map(d => d.State)) .range([0, width]) .padding(0.1); // 2. Y Scale: Nested d3.max to find the highest cumulative upper bound const y = d3.scaleLinear() .domain([0, d3.max(series, d => d3.max(d, cell => cell[1]))]).nice() .range([height, 0]); // 3. Color Scale: Map each age bucket to a color scheme const color = d3.scaleOrdinal() .domain(keys) .range(d3.schemeBlues[keys.length]); const svg = d3.create("svg") .attr("width", width + marginLeft + marginRight) .attr("height", height + marginTop + marginBottom); const g = svg.append("g") .attr("transform", `translate(${marginLeft}, ${marginTop})`); // Render Axes g.append("g") .attr("transform", `translate(0,${height})`) .call(d3.axisBottom(x)); g.append("g") .call(d3.axisLeft(y).ticks(10, "s")); // "s" formats large populations cleanly (e.g., 5M) // Render Stacked Bars using nested elements g.selectAll(".series-group") .data(series) .join("g") .attr("class", "series-group") .attr("fill", d => color(d.key)) // Color each group by its age bucket key .selectAll("rect") .data(d => d) // Bind the individual state intervals within this bucket .join("rect") .attr("x", d => x(d.data.State)) .attr("y", d => y(d[1])) // Top of the bar piece .attr("height", d => y(d[0]) - y(d[1])) // Base height minus top height .attr("width", x.bandwidth()); return svg.node(); }34:T443,testYourKnowledge([ { title: 'SVG Paths', backText: [`SVG Paths have their own mini-language for generating custom shapes. They use commands like M and L that mean "MoveTo" and "LineTo" respectively`, `There are many different commands for generating complex shapes.`], question: "SVG Paths have their own mini-language for generating custom shapes.", answer: true }, { title: 'Line Charts', backText: [`d3.line() is a function for creating the SVG Path attributes, given a dataset`, `You can style your line by supplying an optional curve factory.`], question: 'd3.line() is a function for styling line charts, like adding their stroke color.', answer: false }, { title: 'Stack Layouts', backText: [`The D3 stack function calculates the cumulative total of values across a set of keys.`, `While these value can be used for computing the layout, the function itself does not calculate out the positioning of elements.`], question: `Stack layouts compute the layout of all the rectangles in a stacked bar chart.`, answer: false }, ], 300, 300)35:[{"id":"3ea96de39eb40936da1c5e7bf932e124861c50b9e45569cb17e694e9b9ed462c79684b2ede7266422ee880930d43408010a4741695709c094f9f6827c62534db","href":"https://static.observableusercontent.com/files/3ea96de39eb40936da1c5e7bf932e124861c50b9e45569cb17e694e9b9ed462c79684b2ede7266422ee880930d43408010a4741695709c094f9f6827c62534db","name":"us-population-state-age.csv","type":"text/csv","lastModified":1779138093981.81,"size":3516}] 2f:{"id":"ad2aba08fe94b4f4","slug":null,"title":"Sisi Introduction to D3 Course: Lesson 3","thumbnail":"49e3b8e7b5c25c76853ac31b4ed41e895e2facb91573182f4e68e995d0ccb899","access_level":"public","create_time":"$D2026-05-18T21:01:33.981Z","update_time":"$D2026-05-18T21:14:45.945Z","view_time":null,"first_public_time":"$D2026-05-18T21:44:13.699Z","has_unpublished_edits":null,"fork":{"id":"855def707ff78455","slug":"introduction-to-d3-course-lesson-3","title":"Introduction to D3 Course: Lesson 3","owner":{"id":"f35c755083683fe5","login":"observablehq","name":"Observable"}},"stars":0,"starred":false,"owner":{"type":"team","id":"9409263e557ef66a","login":"dv-develop-2026s","name":"🪦 dv develop 2026 spring","avatar_url":"https://avatars-next.observableusercontent.com/83690145de7111a45dea712eea168cd084ea0cae2d94bdcfa6f9f12e6402cad6","tier":"education_2026"},"version":277,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"aa99df3a6fb6674d","login":"sisi2","name":"Sisi","avatar_url":"https://avatars-next.observableusercontent.com/d31c20cac024f6372a84a376a83cae25107276e3c424f915425b5e7f65ee4623","tier":null}],"members":[{"type":"team","id":"9409263e557ef66a","login":"dv-develop-2026s","name":"🪦 dv develop 2026 spring","avatar_url":"https://avatars-next.observableusercontent.com/83690145de7111a45dea712eea168cd084ea0cae2d94bdcfa6f9f12e6402cad6","tier":"education_2026","role":"editor"},{"type":"individual","id":"aa99df3a6fb6674d","login":"sisi2","name":"Sisi","avatar_url":"https://avatars-next.observableusercontent.com/d31c20cac024f6372a84a376a83cae25107276e3c424f915425b5e7f65ee4623","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Sisi Introduction to D3 Course: Lesson 3","cells":[{"id":5,"value":"# Sisi Introduction to D3 Course: Lesson 3\n## Line Charts & Bar Charts\n\n[Session 3 slide deck](https://docs.google.com/presentation/d/1zjmdZPXXm6Nq7UFm4Yj1pcZgAtZ3_rJCdjIOoqKrCT0/edit?usp=sharing)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":6,"value":"---\n## Activity 1\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":41,"value":"### SVG Path\n- Create a new SVG Path of a diagonal line from the top left corner to the bottom right corner.\n- Create a new SVG Path of a triangle\n\n*For reference, here is a list of all the [path commands](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/d#path_commands).*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":50,"value":"","pinned":true,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":256,"value":"","pinned":true,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":43,"value":"note(md`__Note:__ to automatically close an SVG Path, write Z at the end of our path code.`)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":27,"value":"---\n## Activity 2\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":65,"value":"### D3 Path Generators\n- Create a path generator that takes the values [0, 10, 5, 20] and draws a straight line to each point.\n - For the x axis, you can use the index of the points.\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":67,"value":"myData = [0, 10, 5, 30]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":123,"value":"{\n const width = 500;\n const height = 100;\n const margin = { top: 10, bottom: 30, left: 10, right: 10 };\n\n const svg = d3\n .create(\"svg\")\n .attr(\"width\", width + margin.left + margin.right)\n .attr(\"height\", height + margin.top + margin.bottom);\n\n const g = svg\n .append(\"g\")\n .attr(\"transform\", `translate(${margin.left}, ${margin.top}`);\n\n const x = d3\n .scaleLinear()\n .domain([0, myData.length - 1])\n .range([0, width]);\n\n const y = d3\n .scaleLinear()\n .domain(d3.extent(myData))\n .range([height, 0]);\n \n const line = d3\n .line()\n .x((d, i) => x(i))\n .y(d => y(d));\n\n g.append(\"path\")\n .datum(myData)\n .attr(\"d\", line)\n .attr(\"fill\", \"none\")\n .attr(\"stroke\", \"steelblue\")\n .attr(\"stroke-width\", 5);\n\n return svg.node();\n\n return svg.node();\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":71,"value":"note(md`__Hint:__ you will need to define scales.`)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":28,"value":"---\n## Activity 3\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":96,"value":"### Build Your First Line Chart\n- Convert this Scatterplot* into a line chart using the D3 Path Generator\n\n*Note axes components*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":76,"value":"$31","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":100,"value":"note(md`__Hint:__ You only need to create one path, so you want to use .datum() instead of .data()`)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":29,"value":"---\n## Activity 4\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":131,"value":"### SVG Rect\n- Create a new rectangle that is 50 pixels wide, starts in the middle of the SVG, and is 100 pixels tall.\n- Make the rectangle end at the bottom of the SVG.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":126,"value":"","pinned":true,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":30,"value":"---\n## Activity 5\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":118,"value":"### Build Your First Bar Chart\n- Convert this Scatterplot to a Bar Chart","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":251,"value":"appleStockData.filter((d, i) => i < 20)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":108,"value":"$32","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":150,"value":"---\n## Activity 6\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":157,"value":"### Stack Layout\n- Create a new stack layout function, using the population dataset by state, making the keys the various age buckets.\n- Create a stacked bar chart with the x-axis being each state, and the y axis being the total population, bars colored by their key.\n - Use a band scale to handle for the bar widths\n - Nest a d3.max within the d3.max to get the max y scale value.\n - Use a nested structure to our elements, so that there is a group for each key.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":165,"value":"populationData","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":182,"value":"keys = [\"<10\", \"10-19\", \"20-29\", \"30-39\", \"40-49\", \"50-59\", \"60-69\", \"70-79\", \"≥80\"]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":163,"value":"stackLayout = d3.stack()\n .keys(keys)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":161,"value":"$33","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"---\n## Wrap Up\nTest your knowledge from session three with these short questions.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":8,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":9,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":10,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":11,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":12,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":13,"value":"---\n## Appendix","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":82,"value":"appleStockData = aapl","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"import {note} from \"@observablehq/callout-boxes\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":15,"value":"import { showMe } from \"@observablehq/show-me\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":16,"value":"import {testYourKnowledge} from \"@observablehq/test-your-knowledge-cards\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":17,"value":"color = d3.schemeBlues[7]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":174,"value":"populationData = await FileAttachment(\"us-population-state-age.csv\").csv({typed: true});","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1"}} 30:"$2f:body"