Numbering points that are contained in polygons in QGIS

Question

In QGIS 3.16.8-Hannover I have a layer with polygons and I have a layer with points. Each polygon contains a certain number of points, I would like to assign a number to each point in sequential order in the attribute column "Sequence".

'Polygon A' - Has 10 points, in this case, I would have point with "Sequence" value of 1, then a point "Sequence" value of 2, and so on up to 10.

'Polygon B' - has 12 points, it would be the same as above just it would go up to 12 instead.

See https://gis.stackexchange.com/a/409438/88814 – Babel Nov 15 '22 at 09:12 — Babel, Nov 15 '22 at 09:12

Taras · Accepted Answer · 2022-11-15T07:00:06.287

6

Create the "Sequence" attribute with this expression using the Field Calculator:

if(overlay_within('polygon'), -- name of the polygon layer
    array_find(
        array_agg(
            "id", -- id field in the point layer
            group_by:=overlay_within('polygon', "id") -- any field from the polygon layer
            ),
        "id" -- id field in the point layer
        ) + 1,
    NULL)

References:

edited Nov 15 '22 at 07:00

answered Nov 14 '22 at 17:02

Taras

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"id", -- id field in the point layer
Can it be fid?
– Ghostwriter84 Nov 15 '22 at 07:59
1

@Ghostwriter84 yes, of course! – Taras Nov 15 '22 at 08:19

Numbering points that are contained in polygons in QGIS

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