A buffer is the band of ground within a set distance of something. Everything within 50 metres of a road, within 10 metres of a river bank, within 2 kilometres of a depot — draw the thing, choose the distance, and the buffer tool shades in the zone around it. "Buffer" is the GIS word for it, but the idea needs no jargon.
Doing this by hand means guessing, and doing it properly usually means desktop GIS software. This tool sits in between: pick a shape that is already on your map, type a distance, and get the zone as a real, exportable shape in a couple of seconds.
How it works
The buffer is calculated on the geometry of the layer you choose, not on the pixels on screen, so the zone keeps the same real-world width all the way around. A point becomes a circle, a line becomes a corridor running either side of it, and the result is added as a new layer with its distance recorded underneath its name.
Areas behave differently and it is worth knowing before you use one: buffering a polygon produces a band that hugs its outline — everything within the chosen distance of the border — with the middle left empty, rather than the whole filled shape grown outwards. That is what you want for a setback or a boundary zone.
How to use the Buffer Zone Tool
- 1
Put something on the map first
Draw a shape, take a measurement, or open a data file. The buffer tool works on a layer that already exists, so there is nothing to buffer on an empty map.
- 2
Open the buffer tool and pick a layer
Open the MapGO workspace, choose Buffer, and select the layer you want to wrap a zone around from the dropdown.
- 3
Set the distance
Type the distance and choose metres or kilometres. Decimals are allowed, so 0.5 km and 500 m give the same zone.
- 4
Create the buffer
Press Create buffer. The zone is drawn as a new layer and the map zooms to fit it, with the distance you used kept under its name.
- 5
Style, export or delete it
Rename the buffer, give it a colour from the palette, or remove it. Like every other layer it can be exported as a GeoJSON file from the Layers panel.
What people use it for
Setbacks and exclusion zones
Show the strip of land within a required distance of a boundary, watercourse or structure when preparing a plan or an application.
Corridors along a route
Wrap a fixed width around a road, pipeline, cable run or footpath to define a working corridor or a study area.
Catchment and proximity
Draw the zone within a set distance of a site to see what falls inside it, and compare that zone against other layers on the map.
Notification and consultation areas
Produce the area within a stated distance of a site that has to be notified or surveyed, and export it as a shareable file.
Frequently asked questions
- What is a buffer, in plain English?
- It is the area within a given distance of something. A 100-metre buffer around a school is every bit of ground that lies within 100 metres of it. The tool draws that area as a shape you can see, style and export.
- What distances can I use?
- Any positive number, in either metres or kilometres. Decimals work, so you can buffer by 2.5 m or by 7.5 km just as easily as by a round number.
- What happens when I buffer an area rather than a point or a line?
- You get a band that follows the outline of the area at the chosen distance, with the interior left empty — the zone around the border. Points produce a filled circle and lines produce a corridor.
- What can I buffer?
- Anything on the map with geometry: shapes you have drawn, measurements you have taken, data files you have opened, and analysis results. Heatmap layers are the one exception — the buffer tool leaves them out of its layer list.
- Can I get the buffer out as a file?
- Yes. A buffer is a normal layer, so it can be exported on its own as GeoJSON, or included when you download the whole map as one GeoJSON file.