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I created a Map with Geocoded Addresses from the UK. The Basis for the map is a UK districts shapefile, this constitutes my main layer. After geocoding (via .csv) 3 Addresses I have a new layer with the three Address-Points.

enter image description here

The goal is now to create a Buffer around the Address Point that spans or fills out the entire area of the postcode to which that Address belongs. How can I implement this?

In the picture I included an example with a normal Buffer (just a circle with radius = x) the goal would be to fill the whole postal area with the Buffer.

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    Hi welcome to GIS SE. Please include a tag of what software you're using. Also there's no image attached. Oct 20, 2020 at 15:14
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    there is no picture - wouldn't doing point in polygon and then coloring the polygons be easier than buffering?
    – Ian Turton
    Oct 20, 2020 at 16:03
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    Are you talking about Postcode Districts? en.wikipedia.org/wiki/…
    – Mapperz
    Oct 20, 2020 at 17:23
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    Be aware about terminology: what you ask about is not a "buffer", but to apply a style to a polygon based on spatial relationship.
    – Babel
    Jan 8, 2022 at 10:46

3 Answers 3

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You do not mention what software you are using but the workflow is the same for ArcGIS, ArcGIS Pro, or QGIS:

  1. Create Voronoi polygons around your three points at an extent greater than the postcode polygon. For QGIS see Voronoi Polygons in Processing tools under Vector Geometry. For ArcGIS see ArcToolbox - Analysis Tools - Create Thiessen Polygons (advanced license only).
  2. Clip the resulting Voronoi polygons with your postcode polygon. In QGIS try Vector Overlay - Clip, for ESRI try ArcToolbox - Analysis Tools - Extract - Clip.
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If you are interested in filling the polygon would it not be more convenient to select the polygon based on the point location (Vector - Research Tools - Select by Location) and then saving these into a new polygon layer?

If you use this approach you would have to modify the polygon's attributes to reflect those of the point.

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Be aware about terminology: what you ask about is not a "buffer", but to apply a style to a polygon layer based on spatial relationship from another layer: highlight the polygon that contain points. Easiest to achieve this is to use Geometry generator to add an additional symbol to the point layer: the polygon that the point is within.

To do so, on the point layer, add a new symbol layer of type Geometry generator and add this expression (replace polygon with the name of your postcode layer):

overlay_within('polygon',$geometry)[0]

All countries that contain a red point are styled in blue filled style: enter image description here

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