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Questions tagged [geometry-generator]

For questions about the geometry generator symbol layer style in QGIS.

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3 votes
1 answer
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Draw line and calculate distance from each no adjoining side polygons to perpendicular nearest side polygon

From a polygon geometry layer representing building boundaries, I show a screenshot: I would like to calculate, for each building polygon, the distance from each side of the polygon that has no ...
Ingrid Ingravida's user avatar
1 vote
1 answer
33 views

Geometry still set as point when creating lines in QGIS Geometry Generator

I'm using QGIS to analyze coastal erosion and have come across an issue with geometry type. I have a vector layer of about 150 control points along the shoreline and used a geometry generator to ...
Aubree's user avatar
  • 11
0 votes
1 answer
34 views

Rotate an overview polygon generated to match the area of a map view in print composer?

From an answer in the below question, I can generate a polygon around a LineString input to generate an Atlas. The polygon represents the Atlas view area, given the map's scale, width and height. ...
user15260458's user avatar
1 vote
1 answer
46 views

QGIS: draw line from one point to many points in another layer using geometry generator

Using the geometry generator I would like to draw a line to each point that is within another layer. ChatGPT gave me this, which I think is close, but not quite. collect_geometries( array_foreach(...
Gregory C's user avatar
  • 373
0 votes
1 answer
57 views

QGIS - issues with Geometry Generator

I am experiencing some issues eith the Geometry Generator (GG) in QGIS (I tested it both on 3.28.7 and 3.34.5 versions). I had previously created a point layer with a double symbology, a point and a ...
HyPhens's user avatar
  • 520
3 votes
1 answer
47 views

Mid_point label placement using Geometry Generator in QGIS

I've tried to place a label at the start, end, and middle of my lines in QGIS using the Geometry Generator. This post, place-label-along-line-near-start-and-end-of-line-in-qgis, got me the start and ...
Nick_Jo's user avatar
  • 158
1 vote
1 answer
66 views

Geometry Generator : Make_line between points in QGIS

I'm having difficulty with the geometry generator. Here is my very basic code: make_line( geometry(get_feature('New_scratch_layer_f7ec7875_1bec_46b6_84dd_46bca8f2d978', 'name', 'a')), geometry(...
Gregory C's user avatar
  • 373
3 votes
1 answer
69 views

QGIS Draw line form nearest parcel midpoint side facade to point

I have the following two layers: 'PARCEL' with polygon geometry corresponding to parcels. 'POINTS' with point geometry corresponding to the segmentation of the 'WAYS' layer at a distance of hectometer....
Nil Aspinall's user avatar
0 votes
2 answers
40 views

Label anchoring and placement settings (geometry generator label placement by plugin)

I'm trying to set up a plugin applying custom labels for lines created by Geometry Generator. I want the labels to be "on line", something that's easily set manually: Based on documentation ...
svn's user avatar
  • 101
2 votes
1 answer
46 views

Aggregate/group points by value, and label aggregated point with aggregate expression (QGIS)

Problem Statement I have a layer of multiple points, and I am trying to: Aggregate/group the points by their attribute values, so that one point is drawn for each group of points with matching ...
MarcusR's user avatar
  • 135
2 votes
1 answer
47 views

Setting symbol type and render units in a Python script (plugin) for geometry generator layer

I have a Geometry Generator symbol for layer, created by a script (QGIS plugin). This is line symbol (make_line(), inside some translate/offset_curve transformations), but when added it is displayed ...
svn's user avatar
  • 101
0 votes
0 answers
53 views

geometry_generator not working properly in QGIS Print Composer

I'm working with QGIS 3.34 and trying so draw some lines with a given distance via the geometry_generator: The Pagesize ist 297x1399 mm I draw a shape (rectangle) with Length and Height via @...
reD's user avatar
  • 1
2 votes
2 answers
38 views

Direction arrows (or lines) at node

I've got a set of lines "passing through" a node. The passing links are directional (not all possible combinations) I want to make arrows (line with marker) for each node to display what is ...
svn's user avatar
  • 101
6 votes
2 answers
299 views

Rotate a Geometry Generator expression with a 180 degrees rotation

From a point geometry layer to which apply a Geometry Generator expression to creates a new geometry, my goal is to translate this expression rotating 180 degrees, and taking as reference the opposite ...
Ingrid Ingravida's user avatar
3 votes
0 answers
94 views

Topology-aware "waviness" for polygons in QGIS

I am wondering if there is any chance to create "wavy" polygons that respect the topology. In a polygon-layer where the individual features shares boundaries you can easily style each ...
Lenn's user avatar
  • 1,297
1 vote
1 answer
88 views

QGIS Geometry Generator - legend symbol not recognizable (too large)

I created with the QGIS Geometry Generator some symbols for water-management. But somehow in the legend symbols are rendered "too large" when I have as "Unit" - "Map Units&...
sn1ks's user avatar
  • 3,002
1 vote
0 answers
58 views

Automatically generate random points and add to attribute table

I would like if it is possible to modify an attribute table from a Geometry Generator expression. My goal is, while digitizing points (with Add point feature tool), use a Geometry Generator expression,...
Acperience's user avatar
  • 1,122
1 vote
1 answer
65 views

Automatically generate surrounding polygon involving multiple polygons from a layer in QGIS

I'm using QGIS to draw a polygon around a city neighborhood where the boundaries of that neighborhood will be the back of lots or streets. I merged streets and lots into one layer, now I need to draw ...
Kledson Lemes's user avatar
1 vote
1 answer
126 views

QGIS: Label angle and offset based on line symbol applied to point geometry

I have a line layer which is my project axis (red line in the picture). Along that layer I have created points with a spacing of 100 meters. Those point geometries are represented as line symbols. ...
Markus Lang's user avatar
4 votes
2 answers
320 views

Draw a line separating north and south quadrants passing through the centre point

I have a layer with irregular polygons. I use the expression point_on_surface($geometry) to calculate the centre of gravity: I would like a Geometry Generator expression to draw a line separating the ...
Nil Aspinall's user avatar
3 votes
1 answer
82 views

Visualise 2D layer to pseudo 3D via QGIS Geometry Generator

I would like to visualise a 2D object to pseudo 3D via QGIS Geometry Generator I have a polygonal layer of a football field (GPKG format): I use this polygonal layer for a sports analytics project (...
Nil Aspinall's user avatar
4 votes
2 answers
146 views

QGIS: Using marker line to calculate fence post positions and counts

I am making a farm plan in QGIS. One of the layers is the fencing layout (Shapefile / Line String). One of the fields is the post distance. Other is virtual field calculating post amount (length($...
Jozef Fekiač's user avatar
5 votes
0 answers
100 views

Creating convex_hull clusters from hierarchical nearest distances network percentiles in QGIS

I work with a point layer in which I have calculated two fields: "LONGCLOSE" = closest distances to each point I use the following function Computed with this expression: array_sum (...
Acperience's user avatar
  • 1,122
3 votes
1 answer
132 views

QGIS Geometry Generator : Drawing perpendicular line from center point of curved line geometry

I have made an example project to help me illustrate what my problem is. I have about 900 curved lines which i want to label using the geometry generator. My label should consist of a line extending ...
Gregory C's user avatar
  • 373
1 vote
1 answer
69 views

Get only the arc for the angle where the points are distributed for multi point layer in QGIS

According to the question Drawing an arc from coordinate 0,0 to the median distance cluster in QGIS, I have modified the last expression of the user Babel so that it can work with a 'center' layer ...
Ingrid Ingravida's user avatar
3 votes
1 answer
64 views

Make line from each polygon centroid to each adjacent polygon centroid in QGIS

In QGIS I would need a Geometry Generator expression to, from a polygons layer, draws a line from the centroid of each polygon to the centroid of each adjacent polygon
Nil Aspinall's user avatar
0 votes
1 answer
67 views

Getting attribute values from a no geometry table for use in geometry by expression in QGIS

I have a no geometry table (named TABLE) with 3 fields. There are “Station”, “Offset”, and “Angle”. There are many rows of values (real numbers). These values will be used in geometry by expression. ...
Francis's user avatar
  • 169
4 votes
1 answer
244 views

Drawing an arc from coordinate 0,0 to the median distance cluster in QGIS

Starting from points layer with the fields "DISTANCE" and "CLUSTER_ID". "DISTANCE" field stores the straight line distance value of each point relative to the 0,0 ...
Ingrid Ingravida's user avatar
0 votes
1 answer
123 views

Locating point along line at specified distance from beginning of line and at given offset (buffer) from line either left or right using QGIS [closed]

In QGIS version 3.34.2, given a line, how do I locate a point at a given distance from the beginning of the line but also at a given offset (buffer) from the line? I could use either available plugins,...
Francis's user avatar
  • 169
6 votes
2 answers
169 views

Drawing radius for minimal_circle and diagonal for oriented_bbox in QGIS

Based on the expressions: minimal_circle(collect($geometry)) oriented_bbox(collect($geometry)) I would like to use two expression that: For the minimal_circle draw the radius and label its length: ...
emblematica's user avatar
2 votes
3 answers
449 views

Making an octagon using QGIS geometry generator

I am a self-taught QGIS user and am trying my hand at the geometry generator. I have been tasked with creating a map that has gazebos as points. There are so many easier ways to get a polygon like the ...
Madeline Cox's user avatar
6 votes
1 answer
179 views

Differentiating with unique id overlapping/intersecting or isolated convex_hulls in QGIS

From a layer of 2000 points, I have a field with the name 'NUCLEUS' with four categories (1, 2, 3, 4) that identifies each point with a category of density clusters. In red color you can see the ...
Ingrid Ingravida's user avatar
4 votes
1 answer
97 views

Dynamically drawing the polygon formed by nearest points to @map_extent_center in QGIS

From a DEM raster layer I created a set of random points and informed each point with the value of 'ELEVATION'. I also used the following expression to connect the 10 points closest to the @...
Ingrid Ingravida's user avatar
6 votes
1 answer
184 views

Drawing an arc with length proportional to a distance in QGIS

From two points layers: 'ORIGIN' → Origin point at coordinate 0,0 'CLUSTERS' → Points identified by cluster with field "CLUSTER_ID" I am drawing a line from each point in the 'CLUSTERS' ...
Ingrid Ingravida's user avatar
2 votes
2 answers
213 views

Recreating the shape of curved arrows with QGIS Geometry Generator

In QGIS, I have a line layer with straight lines, consisting only of two vertices: start- end endpoint. I can now use Geometry Generator (see below for the expression I use) to create a third point in ...
Babel's user avatar
  • 71.6k
8 votes
1 answer
264 views

Connecting dynamically the 8 nearest lines to @map_extent_center in QGIS

Starting from a points geometry layer, I am working on the following function that has the goal of drawing 8 nearest lines to the @map_extent_center of the map view: make_line( $geometry, @...
Ingrid Ingravida's user avatar
6 votes
1 answer
83 views

How to prevent hidden objects when move extend layer

Related to the question Creating bar chart from point layer using QGIS Geometry Generator, I am using with success the expressions proposed by user Taras in Solution 2 and for user Babel. The two ...
Ingrid Ingravida's user avatar
6 votes
1 answer
115 views

Drawing 10 nearest lines from each point connecting to the centroid of the 5 points nearest to each point with QGIS expression

Starting from a layer with point geometry, my goal is to do two calculations in one Geometry Generator expression. First, for each point, I would like to calculate the centroid for the 5 points ...
Ingrid Ingravida's user avatar
2 votes
1 answer
157 views

QGIS: Geometry By Expression - collect geometries from self selecting line excluding $currentfeature and change geometry [closed]

I am looking for a solution in QGIS in form of an expression that is collecting the geometries that intersect the $currentfeature ( excluding this one - the orange line ) and than iterate over the ...
Denis Crîlov's user avatar
0 votes
0 answers
14 views

Empty error when reading 3D .wkt out put file of Mean Curvature sleleton

I wrote a code that takes the 3D skeleton from the Mean Curvature Skeleton algorithm as an input to .wkt from the Polyhedron Demo program. It extends to the user with the radius it receives from the ...
zahra_kheyrollahi's user avatar
2 votes
0 answers
31 views

Symbology created with geometry generators renders murky in print legend

I have a style that makes use of the geometry generator for a wavy line: the code is as follows, with units set to mm wave($geometry, 6, 1.5) ) When I export the map as a vector format (...
Beni's user avatar
  • 358
4 votes
1 answer
84 views

Error using aggregate funtions in QGIS Geometry by Expression tool

I am encountering an issue while trying to use the make_line function along with geometries_to_array in the Geometry by Expression tool in QGIS. The expression I'm using is as follows: make_line( ...
unknown123's user avatar
4 votes
1 answer
192 views

Creating horizontal lines connecting points using QGIS Geometry generator

I am using the geometry generator to learn how to generate vectors using expressions. Currently, I have a point vector, and I would like to create horizontal lines (shown in red: manually drawn) ...
unknown123's user avatar
1 vote
1 answer
110 views

Moving (snap) lines to nearest features in QGIS

I have two sets of lines: Layer A (a planned network) and Layer B (how the network was realized). The course of the lines on those two layers is similar, but not the same and they do not have the same ...
Jackie's user avatar
  • 11
7 votes
3 answers
657 views

Creating bar chart from point layer using QGIS Geometry Generator

From a layer with point geometry, I store the following fields: "CATEG" which can be A or B "ORDER" which is an autonumeric field sequence without repetitions "VALUE" ...
Ingrid Ingravida's user avatar
0 votes
0 answers
32 views

Change wedge buffers from arcs to slices

I recently updated QGIS to 3.34.0 from 3.22.5 and noticed the program renders wedge buffers differently from what I'm used to. They appear as arcs around a point such as Instead of as slices of a pie ...
Nadka's user avatar
  • 51
5 votes
3 answers
302 views

Symbolising point shapefile in QGIS: half blue half red colored point

I have a point shapefile. I have one point which I want in two colors. One half should be blue, the other one red. It should be divided vertically. I tried the gradient version but it is as it says a ...
Lina's user avatar
  • 233
1 vote
1 answer
100 views

Create alternatingly colored line segment in QGIS

I have a request to carry out a task which resembles Creating alternatingly colored line from points layer in QGIS. Is it possible to achieve an alternation of color between sections (several lines) ...
KQTN's user avatar
  • 13
-1 votes
1 answer
76 views

QGIS smooth geometry generator without success (no change at regional scale, only change at large scale) [duplicate]

I am trying to smooth lines with geometry generator but without succes (at regional scale, only change at large scale ) Any help ? You will find the files in link. https://drive.google.com/file/d/...
Wilcar's user avatar
  • 851
1 vote
1 answer
61 views

Drawn centroid with function make_circle

I'm using the following function to draw a circle at the centroid position of a layer of points grouped by the "ID" field and excluding NULL values: make_circle(centroid( concave_hull( ...
Acperience's user avatar
  • 1,122

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