Overlay problem when importing a CSV file into QGIS

Question

I'm having a problem with certain entities being superimposed when importing a delimited text file in .csv format into QGIS.

It seems that some entities lose their coordinates and copy the coordinates of another entity. Visually, the original data is not visible in the Canva, as it is superimposed on another entity. When we apply a click selection, we see that several entities are selected, whereas we only see one.

We have contacted the data supplier, who tells us that there is no problem with the data used, and that we need to choose the right delimiter when setting up the import. We did choose the appropriate delimiter, but the problem persists.

You can download an extract of the data at the following link:

https://doi.org/10.15468/dl.q9jj2u (2019)

https://doi.org/10.15468/dl.ea42gx (2022)

Answer 1

In this case, the image in the post shows a single observer and therefore a lack of rigor in the measurements. For other observations, the problem is encountered when, for example, two different bird species are observed on the same coordinate point by two different authors and on completely different dates.