geometry-generatorqgis
I'm working in Geometry Generator trying to produce a line from a point in an x,y direction with a specific length of 50m. I have the direction and line but I can't figure out how to specify the length.
make_line($geometry,make_point(x($geometry)+ "A-R-Xvalue",y($geometry)+ "A-R-Yvalue"))
Field example
There is no such site so far. The feature is rather new and usage examples are only starting to emerge now.
For your specific use case, I'd still recommend to create a line layer with all connections. You can then filter this layer using Atlas and don't need to worry about anything else.
You need to make an array from MultiPoint geometry, but you try to make it from the Convex Hull (which is already one element, not multiple).
collect_geometries(
array_foreach(
geometries_to_array($geometry), -- make array from multipoint
-- make convex_hull for each point
convex_hull(
combine( -- combine(combined, combined)
combine( -- combine(buffer, buffer)
buffer(
make_point(
x(@element)-("TreeInfo_Canopy W"/2),
y(@element)),
"TreeInfo_Canopy W"/2
),
buffer(
make_point(
x(@element)+("TreeInfo_Canopy E"/2),
y(@element)),
"TreeInfo_Canopy E"/2
)
),
combine( -- combine(buffer, buffer)
buffer(
make_point(
x(@element),
y(@element)+("TreeInfo_Canopy N"/2)),
"TreeInfo_Canopy N"/2
),
buffer(
make_point(
x(@element),
y(@element)-("TreeInfo_Canopy S"/2)),
"TreeInfo_Canopy S"/2
)
)
)
)
)
)
Move convex_hull( line to top line if you need the convex hull for the buffers of all points in the multipoint.
convex_hull(
collect_geometries(
...
...
Best Answer
Given a your layer is in a projected (metric) CRS, this should do it:
Since I dont know what your field contains you may need to adjust the content of
atan2(). It expects atan2(dy: y coordinate difference,dx: x coordinate difference). In pseudocode: