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From the following table structure with the fields "ORIG_LATITUDE", "ORIG_LONGITUDE", "DEST_LATITUDE", "DEST_LONGITUDE":

enter image description here

I clarify that the field names describe with their prefix the coordinates belonging to the Origin (ORIG) and Destination (DEST).

I would like to draw an arrow with the make_line function that connects the point defined by the fields of each record "ORIG_LATITUDE", "ORIG_LONGITUDE" with the fields "DEST_LATITUDE", "DEST_LONGITUDE", as shown in this image

enter image description here

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Use this expression:

make_line(
   make_point("ORIG_LON", "ORIG_LAT"),
   make_point("DEST_LON", "DEST_LAT")
   )

If you have a data-only table, without geometry, there are two options: load the table as a point layer first (as recommended by @J.R) or, if you want to avoid this, create directly a new Virtual Layer, containing the lines.

The query in the virtual layer looks like this:

select make_line(make_point(t.ORIG_LON, t.ORIG_LAT), make_point(t.DEST_LON, t.DEST_LAT))
from your_table_name as t

You can then export/save the virtual layer to make the resulting lines permanent (not depending on the table any more).

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  • I understand the idea of this expression, but I understand that it works for a layer with point geometry. In the case of my project, the difficulty I find is that the data source is a table. How can I apply this expression to a table? Do I have to transform the table into a point layer and then apply the expression?
    – Ingrid Ingravida
    Jun 1 at 12:58
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    Yes to use the geometry generator you need to have vector data, a single table wont work. As you have coordinate you may load the table as a point layer first then use @Babel expression
    – J.R
    Jun 1 at 13:06
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    Indeed, thanks @J.R, it's exactly as you say. Another option is to create a virtual layer to avoid loading the initial table as points layer, see updated answer.
    – Babel
    Jun 1 at 14:09
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    @Babel doesn't the make_point use (x, y) or (Lon, Lat) rather than (Lat, Lon) ?
    – J.R
    Jun 1 at 14:45
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    @J.R indeed, you're completely right. I was using dummy coordinates and was so focused on the syntax that this indeed very basic mistake skipped my attention. Good you drew our attention to this, I corrected the answer.
    – Babel
    Jun 1 at 14:58

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