• Blog posts

    Bio

    im1.png

    Question

    How do you create concentric multi-ring buffers in QGIS?

     

    Answer

    QGIS has an inbuilt option to create single distance buffers around, point, line and polygon features. However, to generate concentric multi-ring buffers you can use the QGIS plugin tool named – Multi Ring Buffer.im2.PNG Select the layer that you wish to buffer, and from the Vector menu choose Multi Ring Buffer.

    In the settings:

    • set the Buffer Distance as required e.g. 25 metres (this uses the Distance Units as specified in the Project Settings)
    • the Segments to Approximate to be 100 (the higher the value the more accurately drawn the resulting buffer object will be)
    • the Number of Rings e.g. 3
    • and if required tick to Dissolve features, so for complex line/polygon objects when the buffer self-intersects it will dissolve into one feature

    im3.jpgNow press OK.

    The 3 ring buffer will be created, where each buffer represents a ‘donut’ shape from 0-20, 20-40 and 40-60 metres from the linear object being buffered.

    im4.jpgChanging the layer properties allows you to colour the rings and make them transparent.

    im5.jpgIn addition we can now use the rings to select features that fall within a distance of our linear feature. For example any OS MasterMap buildings within 20-40 metres.im6.jpg