3f:null 40:["$","title",null,{"children":"Stretch Antarctica | XiongBiao | Observable"}] 46:[{"id":"254a99fef9cfdc739794cf276a25ffce226b9d17d64789497bbed4935f1fda7d621149894d3a06e546f0e5c53beda2580db0166433ff2fac65397af1aa3627ea","href":"https://static.observableusercontent.com/files/254a99fef9cfdc739794cf276a25ffce226b9d17d64789497bbed4935f1fda7d621149894d3a06e546f0e5c53beda2580db0166433ff2fac65397af1aa3627ea","name":"countries-50m.json","type":"application/json","lastModified":1773910508026.091,"size":756420}] 44:{"id":"c79a6858b3360e07","slug":"stretch-antarctica","title":"Stretch Antarctica","thumbnail":"54c24e06f064dbd58ec430b81a1d0f214be5475ebc9c98498a180d83c01058f0","access_level":"public","create_time":"$D2026-03-19T08:55:08.026Z","update_time":"$D2026-03-19T12:21:38.588Z","view_time":null,"first_public_time":"$D2026-03-19T12:20:19.123Z","has_unpublished_edits":null,"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":"189a68e88fe366bd","login":"xiongbiao","name":"XiongBiao","avatar_url":"https://avatars-next.observableusercontent.com/a95188709ffcb422fcc635f47420feb25f69fd7305881a42b4a9907e87d2aaf0","tier":"free_2026","bio":"","following":false},"version":167,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"fc82b550d8112553","login":"xiongbiao","name":"XiongBiao","avatar_url":"https://avatars-next.observableusercontent.com/caf2b8f3d51ea1f56efa20730077b94beb57622ab029080cdb84a9ad89ac467d","tier":null,"bio":"","following":false}],"members":[{"type":"individual","id":"fc82b550d8112553","login":"xiongbiao","name":"XiongBiao","avatar_url":"https://avatars-next.observableusercontent.com/caf2b8f3d51ea1f56efa20730077b94beb57622ab029080cdb84a9ad89ac467d","tier":null,"role":"editor"},{"type":"team","id":"189a68e88fe366bd","login":"xiongbiao","name":"XiongBiao","avatar_url":"https://avatars-next.observableusercontent.com/a95188709ffcb422fcc635f47420feb25f69fd7305881a42b4a9907e87d2aaf0","tier":"free_2026","role":"viewer"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":{"id":"dba6dcfe9f1c1226","slug":"projection","title":"Projection","owner":{"id":"189a68e88fe366bd","login":"xiongbiao","name":"XiongBiao"}},"type":"notebook","body":{"titling":"auto","title":"Stretch Antarctica","cells":[{"id":0,"value":"# Stretch Antarctica","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":29,"value":"// \nmap = htl.html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":4,"value":"projection = d3.geoStereographic().rotate([-45, 0])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$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","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":40,"value":"path = d3.geoPath(projection)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$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","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":22,"value":"outline = ({type: \"Sphere\"})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":114,"value":"graticule = d3.geoGraticule10()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":125,"value":"transformedLand = (() => {\n // 深拷贝原始数据\n const copy = JSON.parse(JSON.stringify(land));\n\n // 遍历所有要素\n copy.features.forEach(feature => {\n if (feature.geometry.type === \"MultiPolygon\") {\n // 遍历每个多边形\n feature.geometry.coordinates.forEach(polygon => {\n // 遍历每个环（外环和内洞）\n polygon.forEach(ring => {\n // 遍历每个坐标点 [经度, 纬度]\n ring.forEach(coord => {\n coord[1] = transformLat(coord[1]); // 修改纬度\n });\n });\n });\n }\n // 如果有其他几何类型，可类似处理\n });\n\n return copy;\n})();","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":122,"value":"function transformLat(lat) {\n if (lat <= -60) {\n // 南纬60°以南：从[-90°, -60°] 映射到 [-90°, 0°]\n return -90 + 3 * (lat + 90);\n } else {\n // 南纬60°以北：从[-60°, 90°] 映射到 [0°, 90°]\n return 0.6 * (lat + 60);\n }\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":16,"value":"land = topojson.feature(world, world.objects.land)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":105,"value":"borders = topojson.mesh(world, world.objects.countries, (a, b) => a !== b)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":13,"value":"world = FileAttachment(\"countries-50m.json\").json()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W46","stdlib":"1"}} 45:"$44:body"