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So I've made a number points for a set of locations in the Netherlands. Here they are:

enter image description here

The location of the purple point was computed by means of the “mean coordinate(s)” tool in QGIS. It represents the mean of the coordinates of five student cities in the West of the Netherlands: Amsterdam, Leiden, Delft, Rotterdam, and Utrecht.

I wanted to create a point at the exact same location of this mean, and add it to the existing table of (locations of) student cities I already had. So I looked up the locations of the mean:

enter image description here

And I created a point for which the longitude matches the MEAN_X and the latitude matches the MEAN_Y. Here it is as point number thirteen in the table:

enter image description here

On the map, it corresponds to the yellow (highlighted) location. However, as one can see, the locations of the two points don't match. The points do not overlap one another.

My questions are: why is this the case, and how can I adjust the situation in such a way that the points do overlap? It seems that the coordinate systems of the two points match.

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    What is a point polygon ? Nov 8, 2020 at 12:31
  • @J.Monticolo I'm sorry, I meant to say “points”. I'm new to (Q)GIS terminology. The question has been edited now.
    – Max Muller
    Nov 8, 2020 at 13:08
  • How did you add the mean point to your other shapefile?
    – Erik
    Nov 8, 2020 at 13:08
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    You can't create the point like this: the point will be created where you clicked on the map. If you insert the coordinates, they are saved as attribute values, but not used as geometry-information.
    – Babel
    Nov 8, 2020 at 13:24
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    You can, under QGIS, like you said, create a point anywhere and after, use the Vertex Tool and right click on the point and access to the Vertex Editor Panel and modify coordinates here. See the documentation : docs.qgis.org/3.16/en/docs/user_manual/working_with_vector/… Nov 8, 2020 at 14:36

1 Answer 1

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If you want to create a point with coordinates you know, you can use the function geometry by expression from the processing toolbox. use the expression make_point(x,y) and insert the coordinate-values instead of x and y (be aware of the crs you use).

This will create a new layer. You can copy the created point and insert it in your original points layer, if you want.

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  • Thank you. I'm following the process you described. I think I created a point at the right location. However, I can't select it. When I open the attribute table (of the new layer called "Modified geometry"), I don't see it anywhere. I only see the points of the original points layer. Do you know how I can copy this point and put in in another points layer?
    – Max Muller
    Nov 8, 2020 at 14:40
  • In what CRS is your layer "Modified geometry"? I suppose it's a projection issue. Choose "zoom to layer": do you see a point now? Where is it located?
    – Babel
    Nov 8, 2020 at 14:49
  • I fixed the issue, thank you for your help. It had something to do with the CRS indeed.
    – Max Muller
    Nov 8, 2020 at 15:55

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