A buffer is one of the most common GIS operations there is: take a point, line, or polygon, and generate a new polygon representing "everything within X meters of this." Setback zones around a pipeline, service radii around a facility, protection zones around a river — all buffers. The operation is conceptually simple. Getting the distance actually right is where most quick attempts go wrong.
The mistake that silently ruins buffer distances
Shapefiles and GeoJSON usually store coordinates in latitude/longitude — degrees, not meters. If you buffer directly on raw degree coordinates, a "500 m" buffer near the equator and the same "500 m" buffer near a pole represent completely different real-world distances, because a degree of longitude isn't a fixed distance — it shrinks as you move away from the equator. The result looks like a buffer, but the number on it is wrong.
Three buffer types, and when to use each
- Simple Buffer — one fixed distance applied to every feature. Use this for a straightforward setback, like "50 m around every building."
- Buffer by Feature — a different distance per feature, driven by a column in your data. Use this when different points need different radii — say, larger facilities need a wider buffer than smaller ones.
- Multi-ring Buffer — several concentric distances at once (e.g. 100 m, 250 m, 500 m), useful for visualizing graduated impact zones rather than a single hard boundary.
How to do it
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Upload your data
CSV, Excel, GeoJSON, Shapefile (as a .zip), or GeoPackage all work. Points, lines, and polygons can all be buffered.
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Choose your buffer type and distance
Pick Simple, By-Feature, or Multi-ring, set your distance and unit (meters, kilometers, feet, or miles), and preview the result on the map before committing.
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Export
Download as GeoJSON, Shapefile, GeoPackage, CSV, KML, or DXF — whichever your next step needs.
Ready to buffer your own data?
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