I have read Creating random points in QGIS with values from Attribute Table, but it doesn't address my question because I use the same process:

Vector > Research Tools > Random points inside polygons (variable)

I am presented with the following console:

enter image description here

The attribute NUMFARMS is in the attribute table, is integer-valued, and contains 0s for most of the features. Some of the features have a value higher than 1.

The randomly generated points, however, are only ever one per polygon. What am I doing wrong?

EDIT: In response to a comment, here is a screenshot of the Fields tab:

enter image description here

  • You are definitely did not use 'Random points inside polygons (fixed) when you only got one per polygon, as this is what this will do? I know I can see your screenshot is '(variable') but I have replicated everything that I can see above and it is working as it should for me. I am using QGIS 2.18.12. Sep 19 '17 at 21:47
  • Can you screenshot your layer properties > Fields tab Sep 19 '17 at 21:48
  • @MartinHügi please see the edit above. I am using 'Random points inside polygons (variable)', not fixed, as I want a different number of points ('NUMFARMS') in each polygon. For example, in the first polygon, there are 12 farms, so there should be 12 points at random locations within the polygon. I am using QGIS 2.18.9 for Mac (Mac OS X Sierra 10.12.16) Sep 20 '17 at 15:09

I am a complete novice with GIS, so I failed to notice the obvious.

The Coordinate Reference System (CRS) gave distances in degrees (I had EPSG 4269, which was the default). I wanted to work with metres.

When I entered a minimum distance of 500.0 apart from one another, that was impossible, so QGIS assigned only one point per polygon. When I removed this restriction, it still only put one point per polygon, so I think this was not the only problem.

I had to change my CRS to one that works with metres. I chose UTM, and found the appropriate zone (since I'm in Canada, I used this website). Then:

1) Right click on the layer

2) Click 'Save As'

3) Next to the CRS field, click 'Select CRS' (which is a small icon)

4) In the 'Filter' field, type the CRS you want (in my case, when I Googled 'UTM zone 14', I got EPSG 32614, and that's what I entered in 'Filter').

5) Click the result to make sure it's highlighted, then click 'OK'.

Note this might give you a save error. To get around this:

Next to 'File name', click Browse.

Navigate to a directory in which you would like to save your file. Click it. This enters the entire path into the 'File name' section.

Rename 'Untitled' to something meaningful, and save.

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