2f:T17d6,# Plot Twist, December 2022 *The newsletter about [Observable Plot](https://observablehq.com/plot?utm_campaign=plotpromo&utm_source=newsletter).* ## Special Edition: Plot.geo("Hello, World") We are delighted to announce the new release of Plot, version 0.6.1, which includes… maps! The new **geo** mark renders GeoJSON geometries such as polygons, lines, and points; it works hand in hand with Plot’s new **projection** system to help you produce thematic maps. When Mike Bostock and Fil Rivière recently presented Plot.geo to the Observable team, Mike said: _“Here’s what makes the geo mark exciting: it’s not just that it’s a great way of working with maps of all kinds. It’s that this builds on all the cool stuff that already exists in Plot. It takes the scales, facets, initializers, hexbins, density, Voronoi and more. It all magically works, hand-in-hand with Plot.geo.”_ Four new documentation notebooks show the many dynamic ways you can work with Plot.geo. --- ## 1. Mapping with Plot Plot can now produce [thematic maps](https://observablehq.com/@observablehq/plot-mapping?collection=@observablehq/plot-geo?utm_medium=newsletter). For example, the choropleth map below shows unemployment rates by U.S. county. [

](https://observablehq.com/@observablehq/plot-mapping?collection=@observablehq/plot-geo?utm_medium=newsletter) The Plot.voronoi and Plot.delaunay marks happily consume the projected coordinates (in screen/pixel space). For example, this voronoiMesh mark draws the catchment area of each store: [

](https://observablehq.com/@observablehq/plot-mapping?collection=@observablehq/plot-geo?utm_medium=newsletter) Start mapping here --- ## 2. Plot.geo The [geo mark](https://observablehq.com/@observablehq/plot-geo?collection=@observablehq/plot-geo?utm_medium=newsletter) draws geographic features and other polygonal geometry, often as maps. [

](https://observablehq.com/@observablehq/plot-geo?collection=@observablehq/plot-geo?utm_medium=newsletter) The geo mark’s geometry channel can be used to generate geometry from a non-GeoJSON data source. For example, to visualize the shockwave created by the explosion of the Hunga Tonga–Hunga Haʻapai volcano on January 15, 2022 with a series of geodesic circles of increasing radius: [

](https://observablehq.com/@observablehq/plot-geo?collection=@observablehq/plot-geo?utm_medium=newsletter) Start mapping here --- ## 3. Projections Plot’s new projection system opens the door for all kinds of geographic maps. Once set, the projection option takes over the x and y scales and considers associated channels as _jointly_ describing a location on a surface, typically the globe of the Earth. Plot has a handful of built-in projections that allow to make maps, both large-scale—to draw a region, a city, or even a floor plan—, and small-scale, for the entire globe. The classic projections (cylindric, azimuthal, conic) are available as simply as typing _projection: "mercator"._ [

](https://observablehq.com/@observablehq/plot-projections?utm_medium=newsletter) Start mapping here --- ## 4. Extended Projections Literally hundreds of projections have been created over the years, by mathematicians, artists, designers, geographers, cartographers… D3 includes dozens of them in its d3-geo-projection and d3-geo-polygon modules, and they all can be used with Plot. [

](https://observablehq.com/@observablehq/plot-extended-projections?collection=@observablehq/plot-geo?utm_medium=newsletter) Plus, you’re not even limited to what D3 offers; you can even create your own projection. For a fun example, we show a projection that looks like a sheet of paper. [

](https://observablehq.com/@observablehq/plot-extended-projections?collection=@observablehq/plot-geo?utm_medium=newsletter) Start mapping here --- ## Upcoming Events 📅
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| When | Topic | | :--- | :--- | :--- | | [Join Us](https://www.meetup.com/observablehq/events/289610071/) | Jan. 12 | Observable Educators Network: Looking Ahead| *If you would like to host a future Observable Plot Meetup, please contact us at plot@observablehq.com* --- *This issue was edited by [Fil](https://observablehq.com/@fil) and [Maria](https://observablehq.com/@mariaciampa). Please reach out to us by emailing plot@observablehq.com with your suggestions for the next issue.*
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