Questions tagged [qgis-3]

for questions specific to the 3.x series of QGIS.

799 questions with no upvoted or accepted answers
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votes
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35 views

Show all contour line labels in Layout in QGIS

I created a map with labeled contour lines. When I am now adding the map to the layout view not all labels appear (e.g. 2000, 2500 and 3500 meters has a label, but not 3000) [. In the original map ...
2
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0answers
23 views

PyQGIS 3: Create a layer with a primary key

I have written a plugin for QGIS that is importing some data. In this plugin, I can create a memory layer for the data like I have described here https://gis.stackexchange.com/a/349354/10123, but how ...
2
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0answers
33 views

Smooth contour lines/correctly extract contour lines from a DEM in QGIS

I have a DEM obtained as a result of the interpolation of elevation points TIN Interpolatin: I extracted the contour lines in QGIS and the result is this: After I tried to apply the Line Smoothing ...
2
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0answers
25 views

Create a report with filter from different layer using Atlas

I have the following scenario: Layer ‘grid’, with a field called ‘number’ Layer ‘log’ with field called ‘number’ in common with ‘grid’ layer and another field called ‘date’ Layer ‘problem’ with field ...
2
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0answers
36 views

Grouping points by attributes from field with possibly many values

I have a shapefile "cities" with one unique city_id for each city (geometry polygon, although not relevant here) : city_name ; city_id New-York ; 0001 Paris ; 0002 London ; 0003 And a ...
2
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0answers
33 views

Close gaps between some polygons, which are adjacent in reality

I have tens of thousands of polygons (farmer plots) which have been measured while on the fields. This has caused plenty of gaps between some polygons, which is not the reality. I would need to close ...
2
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0answers
35 views

Digitizing control in PyQGIS

I am creating a plugin that digitizes a line by "add line feature " in the "Toggle Editing" toolbar, I want the digitized line to be between two points of a point layer which is a layer different than ...
2
votes
0answers
27 views

Measuring line input in attribute table

I'm using QGIS 3.10.0 A Coruna. I have a polygon layer (buildings) where I would like to measure each side depending on its geographic direction (north, east,...). I'm using the tool "Measure Line", ...
2
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0answers
32 views

QGIS 3.10: Evaluate default values (data source preference) not staying checked on?

Anyone having trouble with "evaluate default values" in QGIS 3.10.1 preferences, under "Data Sources"? When I click the check box and then "OK", I go back to preferences it's unchecked! And default ...
2
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0answers
56 views

How to solve this problem with proportional size data in qgis print composer

I would like to export a map with proportional circle representation for the number of inhabitant of each city. I've used the assistant size of QGIS and created a proportional legend within qgis ...
2
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0answers
32 views

Dropdown option in QGIS 3 processing modeler input?

I have an Excel spreadsheet with multiple sheets of different XY database. I made a processing model in QGIS 3.10, in which I have used 'make points from table' tool to create a point shapefile. But ...
2
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0answers
34 views

Select extent on canvas - QGIS Plugin

I'm designing a QGIS plugin where I'd like to offer the user the functionality to select the extent of a bounding box from the canvas like in some tools like Create grid. I've explored QT Designer ...
2
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0answers
133 views

Data Plotly QGIS 3.10

I'm new with QGIS and Data Plotly and I have a problem with pie charts feature for Plotly. I load a shape in QGIS and I use it with Atlas to display a pie chart depending of the selected area on the ...
2
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0answers
67 views

Processing script returns no layer

I am trying to run a processing script without a user defined layer output. The example below should create a vector layer with one point. The script runs without any error but the layertree is empty. ...
2
votes
0answers
32 views

Why QGIS cannot georeference a Grib2 file with CRS (PROJ.4 and OGC WKT2)?

Situation: I have some .grib2 files that I downloaded from a (supposed to be) reliable source. When I do $ gdalsrsinfo file.grib2 I get: PROJ.4 : +proj=lcc +lat_0=38.5 +lon_0=262.5 +lat_1=38.5 +...
2
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0answers
73 views

QGIS proj4 definition is not valid

In QGIS 3.4 I'm trying to add a custom projection that was used for topographic maps of Suriname in the 1950s. I have the parameters from an article about historical CRS used in the country. Using the ...
2
votes
0answers
35 views

Loading CSV file without geometry in graphical modeler

I'm trying to use the graphical modeler to make a join between a vector point layer and a CSV file which doesn't have geometry data. I tried to use 'Vector layer' as an input for the CSV-file but the ...
2
votes
0answers
61 views

How to properly label colliding labels in QGIS 3.x

Is there a way to properly show the labels when "Show all labels for this layer (including colliding labels)" is selected from label properties? I was looking for adding callout lines for the labels ...
2
votes
0answers
40 views

Keeping a custom form permanent

I'm adding a custom form to one of my attributes fields, I want to create a drop-down menu where there is predecided values to choose from. I'm going into the layer property>Forms>Selecting the ...
2
votes
0answers
49 views

How can I set which layers are visible by default in a geoPDF?

I'm using the latest QGIS version 3.10 that has the option to export to geoPDF. Currently the output has all layers visible. I'd like to set which layers are visible by default, so that the user is ...
2
votes
0answers
43 views

Rule-based color in dataPlotly bar chart in Atlas

I have created an Atlas in QGIS 3.10 and have made a bar chart that changes accordingly to the corresponding Atlas feature. x-axis: area type and y-axis: area in square meters I also managed to set ...
2
votes
0answers
41 views

QGIS 3 Processing tools don't seem to work (can't load output)

I've got a new machine running on Win10 (I was previously on Win7) and I can no longer use... pretty much any algorithm, especially from SAGA. It's probably something to do with environment variables,...
2
votes
2answers
88 views

Loading OpenStreetMap in PyQGIS

I've written a processing script using pyqgis 3.4 which works. The next step I would like to achieve is to load openstreetmaps as the base map from within the processing script. I can do so easily ...
2
votes
0answers
51 views

Speed up reprojecting large raster (38 GB) in QGIS

I'm fairly new to QGIS and Python but nevertheless want to reproject a 38GB-DEM to a custom CRS. (The output file is supposed to be 55GB large - don't know why, but if I don't have >55GB of free disk ...
2
votes
0answers
17 views

Shortest path analysis has unattainable vertices in result from PyQGIS

You can try this code directly in the console. It basically finds the shortest path but I only have unattainable vertices in the result. Do you know how I can correct this? My layer consists of ...
2
votes
0answers
30 views

QGIS 3.x: Show only labels / TilesXYZ TileLayer of labels only

I'm using QGIS 3.6 and the TilesXYZ extension (deprecated for 3.8+) to export tilelayers of my map. I'd like to export a base layer without labels and a label layer to show on top of features. The ...
2
votes
0answers
32 views

How to change a widget type of a field by using python

I'm working on a plugin for QGIS 3.x and I'm looking for an example how I can change the widget type by using Python code. The change should be applied on fields of a vector layer. At the end it ...
2
votes
0answers
29 views

Change the colors of the pie chart in compouse (plot) in QGIS 3.10

When using the new plot command available in QGIS 3.10 for compouse pie chart generation, I didn't find any option to change colors. Is there any way to choose colors?
2
votes
0answers
17 views

Outputting layer as table at end of process

I am in the process of migrating some QGIS 2.x processing toolbox script to QGIS 3.x. I have a collection of scripts that helps in the seismic 3D planning and geometry processing. One of the scripts ...
2
votes
0answers
30 views

Search yields no results in plugins menu

I can't manage to figure out why I can't download any plugins. I have an Internet connection, but it seems like QGIS can't access the online repository of plugins. As an example, I'd like to download ...
2
votes
0answers
12 views

Sharing classes and methods code among processing scripts

I am writing a set of processing scripts for seismic data acquisition (2D and 3D) planning and geometry processing. They are very crude scripts (I'm not a developer) that performs the tasks I meant ...
2
votes
0answers
54 views

Snapping line layer to line layer

I'm working on a project where I need to snap an existing line layer to a different line layer. These lines represent streams and rivers. I'm working within QGIS Maderia 3.4 LTR. I've tried using the ...
2
votes
1answer
90 views

Error while exporting geometry to CSV with MMQGIS

I am importing a DIVA-GIS shapefile into QGIS. It has a lot of polygons on it. My aim is to group different groups of polygons together and dissolve their internal boundaries so that I end up with ...
2
votes
0answers
36 views

System couldn't find given path while running v.split

I'm trying to run the Grass Tool v.split and get the following error message: the grayed outline in German translate to "The System couldn't find the given path" The .exe-files of the grass Tools ...
2
votes
0answers
45 views

Using Python code from QGIS 3.x Graphical Modeler in console?

I want to use "Join Attribute by Location (summary)" processing algorithm in Python console of QGIS 3.10. After design my algorithm process (join sum of field name "abc" form layer 2 (point layer) to ...
2
votes
1answer
547 views

Deep Learning in QGIS: installing Tensorflow

I am trying to install tensorflow (with or without GPU support) with the keras API in the QGIS 3.4 LTR python 3 environment but without success. I do have a working install of tensorflow-gpu that I ...
2
votes
0answers
44 views

Qgis2web mouse cursor changing symbology

Hovering mouse cursor over polygon on QGIS created webpage changing symbology. I´m have exported webpage from QGIS, thru qgis2web plugin. On settings I have checked "Highlight on hover". When I move ...
2
votes
1answer
41 views

QGIS polygonize issue: GDAL DLL load failed

I am using QGIS Desktop 3.10.0 and I have some issues with the polygonize tool. When I run the polygonize tool, a warning shows up saying that there is an “Import Error: DLL load failed” (see Figure 2)...
2
votes
1answer
29 views

Optional variable (with default value) in custom function

Is it possible to use an optional variable (value2) like ... @qgsfunction(args='auto', group='Custom') def my_test(value1, value2=True, feature, parent) .... in a custom function? Using QGIS 3.8 ......
2
votes
0answers
27 views

Selecting features of one layer based on another layer

I have a polygon layer A, then a new layer is created by applying minimum bounded boxes algorithm and then I selected those features in which height and width of bounded boxes is less than 150 and ...
2
votes
1answer
83 views

Moving point A to point B with attributes using QGIS

I have an A layer containing points with a XX attribute. I would like to move (on points A) the points of a layer B with the same XX attribute as A. There is no notion of distances (from a few cm to ...
2
votes
0answers
59 views

Adding raster layer from WMTS URL using PyQGIS

I am trying to add a WMTS raster layer in QGIS 3.8 using Python (for my plugin). I have found this Loading Layers - Raster in the documentation, but I cannot make it work. I tried this: ...
2
votes
0answers
34 views

Point Displacement in MapServer

In QGIS symbology controls there is a "Point Displacment" option for offsetting points that are close visual clarity. Is there a similar control for MapServer?
2
votes
0answers
26 views

Clipping interpolated raster with shape of original point data-set

I have a point dataset with XYZ values. I inserted this layer in QGIS 3.6 via layer > add layer > add delimited layer. Then, I interpolated these points to a raster via interpolation > TIN ...
2
votes
0answers
128 views

Nearest neighbour analysis from existing Excel sheet

I learnt the Nearest Neighbor Analysis from QGIS Tutorials and Tips. The result of this analysis, see image below I know that after running the distance to nearest hub analysis, it produces hub lines ...
2
votes
0answers
44 views

Print composer too many row in attribute table how to split in multiple frame?

In the print composer, I've only added an attribute table and different attribute columns. As I have too many row to display in a single page, I would like to split the table between different pages ...
2
votes
1answer
50 views

QGIS 3.4 set transparency only for some layers below

I‘m working on a geomorphological map of a river and its sourroundings. As a base I have a topographic map and a DEM for the pre-mapping. The topographic map is not accurate enough in the river gulley,...
2
votes
0answers
36 views

Are there project-specific svgPaths for QGIS?

I have a QGIS project that needs custom SVG symbols. These are all in a directory next to the myproject.qgs project file (and FWIW, everything is under version control): myproject/ .git/ ...
2
votes
0answers
34 views

QGIS 3 script new style more parameters

Since QGIS 3.6 there has been introduced a new script style. I am fairly new to this scripting and I would like to ask for the code to do an fix of two layers and after this to make an intersect of ...
2
votes
0answers
56 views

addParameter to raster in Python QGIS plugin

I create a plugin for processing two rasters. I want to set two input layers and one output layer. class CombineRaster: """QGIS Plugin Implementation.""" Input = 'Input raster' Input2 = '...

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