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I need to create a sector grid radiating out from a point of interest. Here is an example that I laboriously put together by hand:

enter image description here

I have found a couple of similar solutions in Generating dartboard shapefiles using ArcGIS Desktop and Drawing wind rose with QGIS from PostGIS? but neither exactly fit my criteria.

Ideally I need each sector to be an individual polygon (for data analysis purposes) and to be able to create this overlay for different sites using parameters to control the number of sectors and radial distances.

How do I generate these shapes in QGIS?

PolyGeo
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Andrew Little
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1 Answers1

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(Too long for a comment but thought this might be helpful in some way.)

There is a plugin called Proportional circles which allows you create a legend broken into x number of segments (polygons) with a radius you can specify. You can download this from the menubar:

Plugins > Manage and Install Plugins...

Center your canvas to your points then click the plugin icon to open the interface. Then go to Legend only:

Proportional circles interface

You might see something like below (the horizontal lines are also polygons) with labelling enabled:

Example

You can remove those 'lines' by identifying them from the Attribute Table in the SECT field where the value is an L:

Attribute Table

As a quick example, I created a new ID field from the Field Calculator using the expression $id to create unique values. I used this to create a categorised style and label the polygons:

Result

Joseph
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    Thank you that is most helpful - I was certain there must be a "standard" method to do this and this fits the bill perfectly. – Andrew Little Sep 18 '17 at 13:27
  • @AndrewLittle - Most welcome! Glad it was helpful :) – Joseph Sep 18 '17 at 13:32
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    @Joseph I didn't know it, really nice effect. – mgri Sep 18 '17 at 14:09
  • @Joseph did the $id labeling method give the result u're showing ? Does that mean the plugin generate the objects in a given order ? What if we want to label the generated polygons using another logic ? – Snaileater Sep 19 '17 at 09:34
  • Oh ... sector and radius are in the attribute table ... it's ok ! – Snaileater Sep 19 '17 at 12:04
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    U will notice that generated polygons of a same "slice" are overlaid. In Joseph's example Polygon 3 is overlaid with 2 which is overlaid with 1. Maybe that does'nt comply with Andrew's computation needs ... – Snaileater Sep 19 '17 at 12:06
  • @snaileater - It's a little strange. If you output the legend as a memory layer then use the Save As... option to save it as a shapefile, the polygons seem to be 'clipped' automatically (i.e. no polygons are overlapping). But if you output the legend as a shapefile, the overlays are there. – Joseph Sep 20 '17 at 09:49