Using multiple XY fields for geometry definition in point layer in QGIS

Question

In QGIS 3.26.3 Buenos Ares I have a set of drill hole point data with XY fields for the planned drill hole location and a second set of fields for the surveyed XY location after drilling.

I want to visualise these data using the surveyed location as the primary, but in the event that the surveyed data doesn't exist (the hole hasn't been drilled/surveyed yet) i'd like QGIS to read from the planned drill hole field. Is this possible to achieve within a single layer? Or do I have to create two layers, one for each criterion?

I think you vave to use two layers. As I understand your data source is csv or xls file? Then you can recalc source data and reload layer. — RainForest, Mar 15 '23 at 08:23
Please, do not forget about "What should I do when someone answers my question?" — Taras, Mar 18 '23 at 08:07

score 11 · Answer 1 · edited Mar 18 '23 at 08:09

11

Use a Geometry Generator style for your point layer with an expression that creates a point based on x/y coordinate values for surveyed locations if it exists and else create a point based on x/y coordinate values for planned locations.

This expression does this based on field names of coordinate attributes called x_surveyed/y_surveyed and x_planned/y_planned respectively:

if (
    x_surveyed is not NULL,
    make_point(x_surveyed, y_surveyed),
    make_point(x_planned, y_planned)
)

Screenshot: red = surveyed, blue = planned holes (here with a slightly different expression, using case...when condition - it works the same):

You could also use two different symbol layers of Geometry Generator type (one for planning, one for surveyed locations) and apply a different style for each. Or use one symbol layer with the solution from above, but define a data-defined override for the color, something like:

if(x_surveyed is not NULL, 'red', 'blue')

References:

Use QGIS expressions to create geometries: difference between geometry generator and geometry by expression

edited Mar 18 '23 at 08:09

Taras

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answered Mar 15 '23 at 08:21

Babel

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Better to have x_surveyed is not NULL and y_surveyed is not NULL – Taras Mar 18 '23 at 08:08
Why that? This would only make sense if there is a value for y, but not for x. In such a case, no point can be created, so this case can be ignored. – Babel Mar 18 '23 at 16:40
Explicit is better than implicit – Taras Mar 25 '23 at 07:23
Short and simple is better than long and complicated ;-) – Babel Mar 25 '23 at 10:13

Using multiple XY fields for geometry definition in point layer in QGIS

1 Answers1