# Buffer lines or paths in Tableau | Buffer Linestring enhancement | New in tableau 2024.1

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2024-03-14
- **Format:** Video · 10 min watch · transcript available
- **Topics:** Data visualisation
- **Tools:** Tableau (background layers, buffer, calculated fields, maps, spatial)
- **Canonical:** https://just-tim.com/posts/buffer-lines-or-paths-in-tableau-buffer-linestring-enhancement-new-in-tableau-2024-1
- **Watch:** https://www.youtube.com/watch?v=AeZEPsQSlxA

I walk through a new enhancement in Tableau 2024.1 that lets you apply the buffer function to line string geometry objects, not just data points. Using the London Marathon route as a shapefile, I show how to create layered distance zones of 100 metres, 500 metres and a kilometre around the route.

## Key takeaways

- The 2024.1 buffer enhancement extends the existing function from working on geometry points to also working on line strings and polygons
- The BUFFER function takes three arguments: the geometry, a numeric distance, and a unit in speech marks such as "m" for metres
- You can connect to a GPX trace converted into a shapefile, but you must connect to the .shp file with all its constituent parts present
- Stack multiple buffer calculations as map layers and reorder them in the marks pane so smaller zones sit on top of larger ones
- Buffer distances are not pinpoint accurate due to background maths, but over marathon distances the distortion is negligible

## Chapters

- 0:00 Enhancement or new feature?
- 1:39 Preparing the London Marathon shapefile
- 2:22 Connecting and plotting the route
- 3:36 Formatting the map
- 4:09 Building buffer zone calculations
- 6:34 Layering and refining the zones

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/buffer-lines-or-paths-in-tableau-buffer-linestring-enhancement-new-in-tableau-2024-1

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena