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\n The Peirce Quincuncial projection map has the interesting property that it can be tiled infinitely on the plane. \n

\n The following map shows examples of shortest distances for the travels (as the crow flies) between the following cities: Geneva, Seattle, Valparaiso, Rio de Janeiro, Madagascar, Tokyo, Shangai, Sydney.\n

\n Check the following links for inspiration and for calculations:\n

Mike Bostock’s notebook on Peirce's quincuncial projection: [@d3/peirce-quincuncial]
Great circle and shortest distance: great-circle distance

\n Check also this dynamic version of the Peirce quincuncial projection.\n

\n
","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":320,"value":"{\n const context = DOM.context2d(width, height);\n context.translate(width / 2, height / 2);\n context.scale(0.5, 0.5);\n context.globalAlpha = map_transparency;\n context.drawImage(map, 0, 0, width, height);\n context.globalAlpha = 1; \n context.drawImage(map, -width, -width, width, height);\n context.rotate(Math.PI);\n context.globalAlpha = map_transparency; \n context.drawImage(map, -width, 0, width, height);\n context.drawImage(map, 0, -width, width, height);\n \n return context.canvas;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"md`---\n\n## Appendix`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":170,"value":"height = 1150;\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":179,"value":"width = height;","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":352,"value":"map_transparency = 0.3","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":185,"value":"color_lakes = '#0ac'","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":239,"value":"color_land = \"#666\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":252,"value":"color_boundaries = \"#999\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":272,"value":"color_routes = \"#e04\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":18,"value":"// We don't display this map\nmap = {\n const context = DOM.context2d(width, height);\n const projection = d3.geoPeirceQuincuncial().fitSize([width, height], {type: \"Sphere\"}).precision(0.1);\n const path = d3.geoPath(projection, context);\n path.pointRadius(0.8);\n \n context.beginPath(), path(graticule), context.strokeStyle = \"#ddd\", context.stroke();\n context.beginPath(), path(land), context.fillStyle = color_land, context.fill();\n context.beginPath(), path(countries), context.strokeStyle = color_boundaries, context.stroke();\n context.beginPath(), path(add_lakes), context.fillStyle = color_lakes, context.fill();\n context.beginPath(), path(routes), context.strokeStyle = color_routes, context.point= \"1\", context.stroke();\n\t\n context.canvas.style.display=\"none\"; \n return context.canvas;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"d3 = require(\"d3@5\", \"d3-geo@1\", \"d3-geo-projection@2\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":29,"value":"graticule = d3.geoGraticule10()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":31,"value":"world = FileAttachment(\"world-50m.json\").json()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":43,"value":"land = topojson.feature(world, world.objects.land)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":249,"value":"countries = topojson.feature(world, world.objects.countries)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":46,"value":"lakes = FileAttachment(\"world-110m_withlakes.topo.json\").json()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":48,"value":"add_lakes = topojson.feature(lakes, lakes.objects.lakes)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":267,"value":"routes = FileAttachment(\"great_circle.topo.json\").json()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W46","stdlib":"1"}} 45:"$44:body"