40:null 41:["$","title",null,{"children":"Vector Mark / Observable Plot | Elena Petruzzi | Observable"}] 47:[{"id":"eda8a802fb7fd7429555174d1054ed864838ed3805a56a3cec27d6e065b8c12eefab55fb777078ef832caa2f6219b6952d5ff1cdd57e39d00bbc91225f14fbec","href":"https://static.observableusercontent.com/files/eda8a802fb7fd7429555174d1054ed864838ed3805a56a3cec27d6e065b8c12eefab55fb777078ef832caa2f6219b6952d5ff1cdd57e39d00bbc91225f14fbec","name":"windgrid.csv","type":"text/csv","lastModified":1679968576507.87,"size":163963},{"id":"7ebf13172c2991b113e842e12db7b01eed9be687daf9316e9c1d5bc77bd9053452a88795a420ce50b83701e1ac5c5b10e2325230a4e89c6938411806e3bdb673","href":"https://static.observableusercontent.com/files/7ebf13172c2991b113e842e12db7b01eed9be687daf9316e9c1d5bc77bd9053452a88795a420ce50b83701e1ac5c5b10e2325230a4e89c6938411806e3bdb673","name":"temperature difference.xlsx","type":"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet","lastModified":1679968914623.677,"size":17168},{"id":"f0fdd2476dbb5833837bbb779523ed93e4caf4cbaf587d54bdb2242dfde24b563cfb19d95da627416b76ca5f4448241dc6c7034e82bd64caa8eeca930de56d61","href":"https://static.observableusercontent.com/files/f0fdd2476dbb5833837bbb779523ed93e4caf4cbaf587d54bdb2242dfde24b563cfb19d95da627416b76ca5f4448241dc6c7034e82bd64caa8eeca930de56d61","name":"temperature difference@1.xlsx","type":"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet","lastModified":1679968987670.161,"size":135931}] 45:{"id":"efb8c8c695962e9f","slug":null,"title":"Vector Mark / Observable Plot","thumbnail":"85239f0937dedf116a9599fa017c5911fbba2e093f45d2421e4eafd8d0a0a0a9","access_level":"public","create_time":"$D2023-03-28T01:56:16.507Z","update_time":"$D2023-03-28T02:03:14.425Z","view_time":null,"first_public_time":"$D2023-03-28T01:56:16.507Z","has_unpublished_edits":null,"fork":{"id":"3347cdaa75bccd52","slug":"plot-vector","title":"Vector Mark / Observable Plot","owner":{"id":"f35c755083683fe5","login":"observablehq","name":"Observable"}},"stars":0,"starred":false,"owner":{"type":"team","id":"e66c202c8bc4737e","login":"elena-petruzzi","name":"Elena Petruzzi","avatar_url":"https://avatars-next.observableusercontent.com/96732b848a57ab110a92c8054b301f63895f00154b16358579bd6e07f99d43af","tier":"starter_2024","bio":"","following":false},"version":220,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"9ef91fa40c8d0294","login":"elena-petruzzi","name":"Elena Petruzzi","avatar_url":"https://avatars-next.observableusercontent.com/96732b848a57ab110a92c8054b301f63895f00154b16358579bd6e07f99d43af","tier":null,"bio":"","following":false}],"members":[{"type":"individual","id":"9ef91fa40c8d0294","login":"elena-petruzzi","name":"Elena Petruzzi","avatar_url":"https://avatars-next.observableusercontent.com/96732b848a57ab110a92c8054b301f63895f00154b16358579bd6e07f99d43af","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Vector Mark / Observable Plot","cells":[{"id":0,"value":"

Vector Mark / Observable Plot

Observable Plot › Marks › Vector · API

\n\n# Plot: Vector\n\nThe **vector** mark represents data as little arrows, typically positioned in *x* and *y* quantitative dimensions, with a given magnitude (*length*) and direction (*rotate*), as in a vector field. For example, the plot below shows the wind speed and direction for a section of western Europe. (Based on a [LitVis example](https://github.com/gicentre/litvis/blob/master/examples/windVectors.md).)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":219,"value":"temperatureDifference1 = FileAttachment(\"temperature difference@1.xlsx\").xlsx()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":40,"value":"Plot.plot({\n inset: 10,\n width: 1152,\n height: 870, // for a rougly equirectangular projection\n color: {\n scheme: \"viridis\",\n label: \"Speed (m/s)\",\n zero: true,\n legend: true\n },\n marks: [\n Plot.vector(wind, {\n x: \"Temperature_Diff\",\n rotate: ({u, v}) => Math.atan2(u, v) * 180 / Math.PI,\n length: ({u, v}) => Math.hypot(u, v),\n stroke: ({u, v}) => Math.hypot(u, v)\n })\n ]\n})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":71,"value":"Per [Remote Sensing Systems](https://www.remss.com/measurements/ccmp/) documentation:\n\n> *Standard U and V coordinates apply, meaning the positive U is to the right and positive V is above the axis. U and V are relative to true north. CCMP winds are expressed using the oceanographic convention, meaning a wind blowing toward the Northeast has a positive U component and a positive V component.*\n> \n> *Longitude is given in degrees East from 0.125 to 359.875 and latitude is given in degrees North with negative values representing southern locations.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":178,"value":"And here is another example using Poisson disk sampling of a Perlin noise field:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":13,"value":"Plot.plot({\n inset: 12,\n height: 1152,\n width: 1152,\n marks: [\n Plot.vector(samples([0, 0, 2, 2], 4000), {\n length: ([x, y]) => (noise(x + 2, y) + 0.5) * 24,\n rotate: ([x, y]) => noise(x, y) * 360\n })\n ]\n})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":191,"value":"noise = octave(perlin2, 2)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":169,"value":"Next \nAPI Reference","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":185,"value":"---\n\n## Appendix","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":182,"value":"import {perlin2, octave} from \"@mbostock/perlin-noise\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":15,"value":"import {samples} from \"@mbostock/poisson-disk-sampling\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W47","stdlib":"1"}} 46:"$45:body"