29:null 2a:["$","title",null,{"children":"Drawing the tropics on a D3 world map | Tom Pearson | Observable"}] 2f:[{"id":"254a99fef9cfdc739794cf276a25ffce226b9d17d64789497bbed4935f1fda7d621149894d3a06e546f0e5c53beda2580db0166433ff2fac65397af1aa3627ea","href":"https://static.observableusercontent.com/files/254a99fef9cfdc739794cf276a25ffce226b9d17d64789497bbed4935f1fda7d621149894d3a06e546f0e5c53beda2580db0166433ff2fac65397af1aa3627ea","name":"countries-50m.json","type":"application/json","lastModified":1676550439137.416,"size":756420}] 2d:{"id":"73e7a84a78406d55","slug":null,"title":"Drawing the tropics on a D3 world map","thumbnail":"e2dd7bf4a4b7d230931f9a415d83cbced085f630437bd6e3f8a9d64819881908","access_level":"public","create_time":"$D2023-02-16T12:27:19.137Z","update_time":"$D2023-02-16T14:24:28.770Z","view_time":null,"first_public_time":"$D2023-02-16T12:27:19.137Z","fork":{"id":"305227651b1938c9","slug":"d3-world-map","title":"D3 world map","owner":{"id":"f35c755083683fe5","login":"observablehq","name":"Observable"}},"stars":0,"starred":false,"owner":{"type":"team","id":"45d8dac961c18abd","login":"tomgp","name":"Tom Pearson","avatar_url":"https://avatars-next.observableusercontent.com/26cbbccc572a8a25c540387278c92aae1c68384373da7f85ef1cd717c7fbf381","tier":"starter_2024"},"version":170,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"08c8ac6bee0bc7e8","login":"tomgp","name":"Tom Pearson","avatar_url":"https://avatars-next.observableusercontent.com/26cbbccc572a8a25c540387278c92aae1c68384373da7f85ef1cd717c7fbf381","tier":null}],"members":[{"type":"individual","id":"08c8ac6bee0bc7e8","login":"tomgp","name":"Tom Pearson","avatar_url":"https://avatars-next.observableusercontent.com/26cbbccc572a8a25c540387278c92aae1c68384373da7f85ef1cd717c7fbf381","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Drawing the tropics on a D3 world map","cells":[{"id":0,"value":"md`# Drawing the tropics on a D3 world map`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":29,"value":"map = htl.html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4,"value":"projection = d3.geoEqualEarth()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":86,"value":"Many other projections are available. [Browse them here](https://observablehq.com/collection/@d3/d3-geo-projection).","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":40,"value":"path = d3.geoPath(projection)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":25,"value":"height = {\n const [[x0, y0], [x1, y1]] = d3.geoPath(projection.fitWidth(width, outline)).bounds(outline);\n const dy = Math.ceil(y1 - y0), l = Math.min(Math.ceil(x1 - x0), dy);\n projection.scale(projection.scale() * (l - 1) / l).precision(0.2);\n return dy;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":127,"value":"tropicOfCancer = d3.range(400).map(i => [i / 399 * 360, 23])","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":149,"value":"lowResCancer = d3.range(8).map(i => [i / 7 * 360, 23])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":129,"value":"tropicOfCapricorn = d3.range(400).map(i => [i / 399 * 360, -23])","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":22,"value":"outline = ({type: \"Sphere\"})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":114,"value":"graticule = d3.geoGraticule10()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":16,"value":"land = topojson.feature(world, world.objects.land)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":105,"value":"borders = topojson.mesh(world, world.objects.countries, (a, b) => a !== b)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":13,"value":"world = FileAttachment(\"countries-50m.json\").json()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W2f","stdlib":"1","titling":"auto"}} 2e:"$2d:body"