Questions tagged [geometry-generator]

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

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3
votes
1answer
46 views

Changing the order of the polygon's nodes using the geometry generator in QGIS

How can I, using the geometry generator, change the order of the polygon's nodes, starting from the most northerly node in QGIS?
5
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3answers
68 views

Generating start and end points for individual road segments

I have shape file with road network (line layer) as shown in Image 1. The road network contains multiple line segments as shown with blue line in image. I am trying to generate start and end point of ...
4
votes
1answer
84 views

Connect points with line using virtual layer

I have 10 points in QGIS layer as shown in Image 1. I am trying to connect points with lines in required sequence as shown in Image 2. However, when I tried to connect all points with virtual layer, ...
1
vote
1answer
29 views

Apply transformation to layer on the fly when using tools like Buffer

I know that you can have an on-the-fly transformation on a layer when rendering on the canvas, but is there a way to run a tool like Buffer where the layer should be re-projected on-the-fly just ...
0
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1answer
24 views

QGIS - Changing the length of Shortest_Line for CAD-like slope pattern?

I haven't found a tool/plugin that could do this, but I am almost there. Here is what I want to do: I want to create a slope like the ones from CAD programms, but I don't have and don't need a DEM. ...
1
vote
1answer
37 views

Export Polygon generated with Geometry Generator as dissolved polygons

Absolute QGIS newbie (3.10.8) here, so please bear with me. I got a QGIS document where some polygons (countries) are virtually dissolved in regions (like South America), through a rule-based ...
3
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1answer
50 views

Relation aggregate function error in QGIS using Geometry by expression

I have a point layer, consisting of 12 points with fid 1 to 12. I want to render points with fid > median (fid) - thus in this case, point 7 to 12. That works perfectly if using geometry generator ...
4
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2answers
98 views

Connecting points with line in a specific sequence

I have 6 points in one layer as shown in the first image. I am trying to: connect points with lines in a required sequence. Save data of line connections (From_point and To_point) in the seperate ...
8
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1answer
111 views

Connecting points with lines and saving starting and ending points in new layer

I have 3 points in one layer as shown in the first image. I am trying to connect a building points with junction point by 2 lines. For demo, I have manually drawn a lines in image 2. Here, I am trying ...
3
votes
2answers
64 views

Making curved line between points by using QGIS Geometry Generator

I am testing different tree crown drawing options in QGIS. At the moment, I have found this option to be the most suitable for me. Code: convex_hull( combine(buffer(make_point($x-("...
1
vote
2answers
44 views

Follow-up query on “QGIS expression for label text to display vertex coordinates of polygons”

Just a follow-up query about the existing thread QGIS expression for label text to display vertex coordinates of polygons. Is there an expression in QGIS to collect all the coordinates from the ...
2
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1answer
99 views

Antipodes map in QGIS

Does anybody know a trick to create an antipodes map with QGIS? That is a map of the world on one layer, and a map of the world on another layer, showing the antipodes of each point (practically a ...
5
votes
3answers
187 views

Creating line from points and counting the number of points on that line

I have a shapefile that contains a number of points, each point represents a tree. I would like to calculate how many trees there are per row. Hence my question (I think this is the best method), how ...
5
votes
1answer
77 views

Using QGIS to draw a line tangential to an existing circle and parallel to existing lines

I am trying to draw a line tangential to a circle and parallel to an existing line. I have drawn the rough shape below showing the lines I need to draw as dashed lines. Using the advanced ...
4
votes
1answer
61 views

Getting the segment of a line, crossed by another with QGIS expression

I have two line layers in QGIS 3.16: line 1 (blue), line 2 (red). The white points are the vertexes (nodes) of the two lines. They have no common vertex, are not connected. How can I get the segment ...
3
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1answer
74 views

How to get a smooth transition between startpoint and endpoint of a line in QGIS?

I have a layer with a few lines. They look very smooth in general, but there is a sharp edge at the start/endpoint of the line. Hot to eliminate that and get the blue dotted result line there?
1
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1answer
83 views

QGIS - Tree crown polygon maping with Geometry generator

I am new to QGIS and I have stumbled on this automatic way to map tree crowns using 4 points - north, east, south, west. Most informative post was this and Solution 2 (8-vertex polygon). The ellipse ...
7
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2answers
212 views

Render all geometries in an array from geometry generator / QGIS expression editor

I have a line layer and want to add a series of 10 single sided buffers with increasing distance: 1, 2, 3... to 10. With geometry generator, I created this valid expression: array_foreach( ...
1
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0answers
52 views

Change size, color for nested styles consisting of different symbol layers created with geometry generator in QGIS

In QGIS 3.16, I have a nested linestyle that consists of different symbol layers. I am able to change the width, color and other settings manually for each symbol layer. However, I want to be able to ...
6
votes
3answers
248 views

Path ending with an arrow: need to improve symbology

Based on @BERAs answer to Arrow head at the last path segment of Bezier curve I made an arrow at the end of a path with geometry generator make_line(point_n( $geometry, -2), end_point($geometry)) I ...
0
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0answers
120 views

Sankey diagram on maps

I want to create sankey diagrams (see: https://en.wikipedia.org/wiki/Sankey_diagram) from date like: zipcodepoly1 zipcodepoly2 value 12345 45789 250000,00 .... I have polygons with ...
2
votes
1answer
57 views

Show polygon features within a polygon from another layer in QGIS

In QGIS 3.14 I am using three polygon layers; one representing buildings, the second representing "city ​​boundaries" and the third representing the municipal boundary. My aim is to show all ...
4
votes
1answer
52 views

QGIS Geometry Generator - Connecting Points with Lines - with a 'one to many' relationship

I'm working with QGIS 3.12 and have two large point shapefiles (buildings/barns and wetlands) that I want to connect with lines via the geometry generator. I've found a function called get_feature() ...
4
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1answer
57 views

Geometry Generator and Zonal Statistics

I am trying to compute population affected by various distances, during earthquake events. The earthquake point events update every minute and I need to find a way how to create automatic buffers and ...
1
vote
2answers
97 views

Splitting rectangles into 2 triangles using Geometry by Expression in QGIS

I am using QGIS 3.10. I am trying to split multiple rectangle polygons diagonally into 2 parts using "Geometry by expression" under Processing. This is for symbology only (exporting for use ...
3
votes
1answer
65 views

How to create a convex hull using QGIS Geometry Generator?

Background: At 3.14.16, I'm trying to learn a little more about Geometry Generator, in this case convex hull. I created a simple test point layer with six points. I then used Geometry Generator with ...
4
votes
1answer
80 views

Transforming line into polygon with Geometry Generator

I would like to turn my line into polygon in the symbology. I found some hint here: https://anitagraser.com/2017/04/08/a-guide-to-geometry-generator-symbol-layers/ but I am not sure of the expression, ...
2
votes
1answer
150 views

Interpolating point on each line from vertex in QGIS

How can I interpolate a point on each line from the vertex? I need to interpolate each vertex along the line for a certain distance. I need offset on all lines. Standard QGIS tools shift incorrectly ...
4
votes
1answer
94 views

Getting x-coordinate of midpoint from line layer

I Need to get a midpoint from a line layer. Property layer -> Style -> Simple symbol -> Generator geometry (line) I have code #1: x(line_interpolate_point($geometry, $length / 2) this code ...
2
votes
2answers
70 views

QGIS: automatically replace values in geometry generator's expression in all symbol layers of a feature

I have created some piecharts in QGIS 3.14 with the geometry generator (see here why it was not possible to use the built-in piecharts from the layer properties). I now have 10 piecharts, each with ...
4
votes
3answers
499 views

Variable width buffer in QGIS

Is there any built-in tool in QGIS that I can use to buffer points to a variable size (I want to circles around the points, with widths dependent on an attribute in the point layer)? The Vector/...
1
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0answers
79 views

QGIS how to select a set of features in field calculator expression

I try to connect one feature from a polygon layer to many in a point layer, using geometry generator and expression calculator in the polygon layer. If I can connect 1 polygon to all the points, ...
3
votes
1answer
273 views

How to use a Processing Algorithm in a expression function used in a Geometry Generator (Points Along Lines “on the fly”)

I want to use the Processing Algorithm, pointsalonglines, in the expression function used in Geometry Generator. This is because I want to create points "on the fly" along my line and in a ...
0
votes
1answer
89 views

QGIS Crashes using Smooth Geometry Generator on Lines from GPKG

I'm trying to use the geometry generator in symbology for a line layer. Specifically I want to smooth out the lines using smooth($geometry,5). Unfortunately QGIS crashes every time I try to implement ...
5
votes
1answer
375 views

Curved arrows in QGIS using geometry generator

I use QgGIS 3.10 and this tutorial https://anitagraser.com/2019/05/04/flow-maps-in-qgis-no-plugins-needed/. I am able to create lines of varying thickness and color depending on the weight of the ...
0
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0answers
40 views

How to create a wavy line on QGIS [duplicate]

I'm looking for a way to quickly transform simple lines into wavy, zigzag lines and so on in QGIS. I already tried to use the method reported by @christoph in a question posted in this forum (Drawing ...
2
votes
1answer
39 views

Dependency of make_ellipse

I can't find anything on google or the QGIS changelog on this issue: We're using a style for points which contains a point, a circle and an ellipse. Point and circle (buffer($geometry,5,80)) work ...
3
votes
2answers
493 views

QGIS Geometry Generator - Connect Point Data with Lines

I have two point data sets; 'Person' (in red) and 'Connections' (in blue). They have matching columns 'Person_UID'. I'm trying to connect the red points to all the blue points that have matching ...
1
vote
1answer
83 views

Create new shapefile from Geometry generator

I have a line shape and used QGIS geometry generator to modify the line. Now I would like to create a new shape file from the new style. Is that possible in QGIS? I'm using QGIS 3.4
2
votes
1answer
62 views

Direction of the orientation of shortest lines by Geometry Generator - Archaeological hachures symbol

I am creating, by Geometry Generator, an archaeological graphical style for lines. The goal is to be able to create automatically "hachures" that connect the external perimeter to the internal line (...
2
votes
1answer
106 views

QGIS geometry generator to SLD

In QGIS I'm using the geometry generator to visualize a point shape file as a line with the simple code: And then I'm doing a graduated styling according to the burial value of those points: So ...
3
votes
1answer
201 views

Using Rule-based/Geometry generator style in QGIS

I have layer for comments in qgis, symbology style is rule based with Geometry generator. Problem is with displaying name in layers tab because the line before text is too long How do I solve the ...
3
votes
1answer
66 views

Labeling only maximum value when zoomed out or print in smaller scale

I would like to prioritise the maximum values to be shown on the map. In other words, when the label collides it should drop out the minimum values. In the shown examples, I would like to have ...
2
votes
1answer
164 views

How to create geometry with geometry functions?

I see there are functions in QGIS that supposed to generate geometry, like geom_from_wkt. How do I actually display it? When I create a new field (in a field calculator) with a formula, say bounds(...
3
votes
1answer
160 views

Building a rectangle around a font marker using the geometry generator

In able to show labels in a legend (see my other question regarding the legend here: QGIS styling a legend) I need to show points as rectangles with the same height but a length based on the length ...
3
votes
1answer
92 views

Set geometry generator polygon to have flat end caps

I'm trying to buffer a line using Geometry Generator in QGIS (buffer($geometry,3)) However although I've set the Simple Fill join style to Miter I can't get the ends of the buffer to be flat. I ...
2
votes
1answer
277 views

Shorten leader-line for labels with geometry-generator

QGIS 3.8, Win 10. I have labels that are connected with the points they represent with a leader-line. The line is generated with geometry generator (going from the point-layer to the position where I ...
5
votes
1answer
117 views

Restricting label/line drawing to 45 deg. lines?

I've followed this tutorial to be able to move label positions and draw lines to connect them to the label dots, but I'd like to restrict the line drawing to 45˚ angles. Is there a way to do that? I ...
4
votes
1answer
212 views

Measure collected polygons in Geometry Generator, avoiding extra texts from multipart polygons

I combined a set of polygons on the first instance of Geometry generator using something like this: buffer(buffer(collect( $geometry, concat("MZNA","REGLABEL")), 0.1), -0.1) Buffers are meant to ...
1
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0answers
66 views

Use of QGIS/GRASS/SAGA procedures on Geometry Generator

Im new at QGIS, started 2 weeks ago. I'm trying to automatize the display of a map and get rid of some "duplicated" layers and all the extra work. I need to know if SAGA's dissolve can be used in the ...