Questions tagged [geometry-generator]

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

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41 views

Converting lat/long to EPSG:27700 in geometry generator expression

I have incorporated a geometry generator into a style in QGIS 3.4 which creates a callout line from a feature to its relevant spatial position. For reasons out of my control our projects use CRS: ...
1
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0answers
35 views

Layer Styling by Geometry Generator in QGIS 3.6

I am trying to create custom styling by using Geometry Generator in QGIS 3.6 but I got an error expression. segments_to_lines ( $geometry) ramp_color('Viridis', scale_linear( length( ...
1
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1answer
39 views

Geometry generator in print composer

I am trying to create folding marks in the QGIS-print composer. Basically they are just markers along a line - with the twist, that the spacing is not even. I want to avoid having to create several ...
4
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2answers
153 views

How to divide a buffer using geometry generator in QGIS 3.X

Some background and working PostGIS query and Python script available here. How to split circles in 12 sections in PostGIS? I don't want to create a new polygon layer out of points. I really like ...
3
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1answer
219 views

QGIS Geometry Generator Line Type

I am trying to create a line style for a multiline geometry. I am hoping to create a linetype which looks like the following The Points are not an issue, its the line/lines entering and exiting at ...
2
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1answer
87 views

Which Units Geometry Generator in QGIS works with?

While modifying some geometries in QGIS in my previous question Adjusting flow map styles in QGIS: Varying buffers' sizes I ended up with a huge confusion regarding the dimensions/units that Geometry ...
3
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0answers
161 views

pyqgis - geometry generator - line pattern fill

I'm trying to make a line pattern fill in QGis using the geometry generator and a python function. The code is inspired from this answer : Save line geometry as points geometry in QGIS (pyqgis) from ...
3
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2answers
220 views

Geometry Generator - Line pattern fill to a buffer of x metres

I have an image below to help illustrate the style I'm trying to apply to my polygon. I have an idea of what I need to type in the geometry generator but can't get it to work. Something along the line ...
2
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0answers
49 views

Unexpected behavior of collect() in geometry generator

I'm having unexpected results using geometry generator with the following expression: buffer(collect($geometry),0) …which was an answer given in this topic. I have used this previously with the ...
3
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1answer
89 views

Using geometrygenerator and different CRS in QGIS?

In a QGIS3-project (QGIS Version 3.4.3) I'd like to display points from a textfile and constructed lines from this points in an given length and an angle from the textfile with the geometrygenerator. ...
3
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3answers
279 views

Draw line to next feature with distance as label (dynamic)

I would like to dynamically draw the shortest line to the next object (Geometry Generator?). Example: I have a network-layer (streets) and a point-layer. I know the distance from every point to the ...
3
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1answer
170 views

Geometry Generator - make line to polygon perimiter

I would like to improve the way arrows point to polygons when moving labels. I have some fields with unique numbers associated with each one. When the centroid of a polygon is outside the physical ...
2
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0answers
49 views

Achieving the opposite of the shortest_line() function in QGIS?

I currently use the Geometry Generator styling on a point layer to draw the intersection between protection buffers around tree points and another polygon (say a building footprint) using the ...
2
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0answers
76 views

How to create pattern fill via geomtry generator in QGIS3?

I would like to style polygon layer using geometry generator to create point patterns but using just generated points geometry. Is it possible? How can I achieve that? I know that I can use just use ...
5
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2answers
152 views

Geometry generator line from centroid to edge of irregular polygon

I have a point layer styled with the following geometry generator formula for an irregular polygon. It is the union of (a) a circular buffer with (b) a tree canopy spread buffered by 1m (where that ...
1
vote
1answer
299 views

Geometry Generator Line to Polygon Feature

I had great luck using Carlos' answer here to make lines from features in a point-shapefile layer to their labels, but when I tried the same technique with a shapefile layer of polygons, it won't work....
3
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0answers
227 views

QGIS draw line segments with “geometry generator” based on segments angle

I have quite a hard problem to solve here and I don't know if its even possible with the geometry functions in QGIS. I have a line geometry with equidistant vertices, that is, same length segments. ...
3
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0answers
101 views

Drawing a line to a point - style in QGIS

I need to create a style in QGIS in which the line is moved away from the second line by 2 units, but their ends merge at one point. I created 3 geometry generators - 3 lines. At the ends of the line: ...
1
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0answers
66 views

Geometry-generated lines not showing on QGIS Cloud

I have a points layer (tested as both a delimted text file and as a point shapefile) which is styled as shown below where the lines were created using the Geometry Generator. Please ignore the ...
1
vote
1answer
199 views

Comparing values across attributes of one feature in QGIS

I am using QGIS 2.18 I have a shapefile that contains data of each state of India, and the number of people per state following a particular religion. Each feature has the following attributes: ...
5
votes
1answer
356 views

Rotating polygon in geometry generator based on feature attribute?

That's a bounding box generated with the geometry generator with variables from a table: geom_from_wkt( 'POLYGON(('|| (x( $geometry ) + ("width"-"bleed")*"scale"/2)||' '||(y( $geometry ) + "height"*...
9
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2answers
408 views

Create an arc of lines from a line and a value

I'm trying to recreate an Origin-Destination plot like this: I have managed to munge the data into a MSOA to LAD table and can draw a map like this for one of the origin MSOA. Which once you allow ...
0
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1answer
414 views

Create callout from label to edge of polygon with Geometry generator with QGIS

With make_line(centroid ($geometry), make_point("x","y")) you can draw a line between the label and the center of an polygon, like this: Is there a way to draw a line just between the border/edge of ...
3
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3answers
508 views

Extract coordinates of lower right corners of polygon

Using QGIS 2.18.14, I would like to know the node number at lower-right corner of each polygon, shown as red circle in a image below. My goal is to obtain xy coordinates, by giving such number n to ...
12
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2answers
338 views

Displaying generated lines out of map extent using QGIS?

I have drawn an OD flow map using QGIS geometry generator, using the following expression : make_line( centroid( $geometry ), centroid( geometry( get_feature( 'Layer2', 'Attribute1', attribute( ...
7
votes
1answer
334 views

Styling shared boundaries in QGIS?

I have 2 polygon layers, 1 showing roads and another showing parking restrictions on those roads (no parking, residents only, etc). I'm trying to style the layer according to the markings that would ...
2
votes
2answers
640 views

How to rotate a geometry created by the geometry builder in QGIS

This topic goes into making polygons based on point locations; Using QGIS Geometry Generator to get rectangle from point? Is there a way to apply a rotation to the geometry generated? I have a field ...
8
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1answer
275 views

Rotate geometry generator marker line depending on map projection QGIS

I'd like to rotate marker line made from geometry generator function: the thing is that, by means of geometry generator I create line via make_line and points are the calculated values (based on ...
1
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0answers
291 views

Creating multiple polygons within one geometry generator using QGIS?

Is it possible to create multiple geom_from_wkt() elements like Using QGIS Geometry Generator to get rectangle from point? in a single geometry generator symbol layer?
3
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0answers
580 views

Geometry generator & get_feature

I am just trying to follow anita graser's examples in https://anitagraser.com/2017/04/08/a-guide-to-geometry-generator-symbol-layers/ - where the "Creating a line between features in different layers" ...
9
votes
1answer
216 views

Using some 'temporary variables' in QGIS Geometry generator symbol layer type expression?

Making use of the Geometry generator symbol layer type, I draw rectangles of dimensions @nv_bg_w (width) and @nv_bg_h (height) (project variables) to line features, either at coordinates text_x, ...
18
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2answers
3k views

Creating leader lines for moved labels

With a lot of help from gis.stackexchange.com I've created leader lines for point symbols. The lines are based on a geometry generator symbology: Shortening line geometry using expression dialog in ...
7
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2answers
974 views

Shortening line geometry using expression dialog in QGIS?

I use the "Offset Point Symbol" tool and a geometry generator symbology to create dynamic leader lines. A sample file is available at http://hub.qgis.org/issues/15201 (Add snapping for 'Offset Point ...
8
votes
2answers
1k views

Seeking QGIS geometry generator manual?

I'd like to create some flow maps like the ones shown in Underdark's post: https://anitagraser.com/2016/12/18/details-of-good-flow-maps/ I have a set of location points, say 50, and I'd like to ...
6
votes
4answers
4k views

Using QGIS Geometry Generator to get rectangle from point?

I would like to translate a point (from a point layer) to a rectangle polygon using the new Geometry Generator from QGIS 2.14. I know the length and the height of the resulting rectangle. The point ...