Questions tagged [qgis-3]

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

Filter by
Sorted by
Tagged with
3 votes
1 answer
236 views

Orfeo mshift segmentation asks for condition

I'm trying to run a segmentation using the mean shift. I leave all the parameters as default, but when I run it, it says "Wrong or missing parameter value: Condition". Condition is not a parameter for ...
6 votes
1 answer
170 views

Using Arabic labels in QGIS

In QGIS 3.30 I am trying to render labels in Arabic. When I turn on the labels, the Arabic text appears mirrored compared to how it is correctly written in the attribute table. Does anyone have any ...
0 votes
1 answer
244 views

Shapefile exported with CRS but CRS unknown when layer added to New Project

After right clicking and saving a defined CRS shapefile I open the layer in a new project, but the CRS is unknown. I thought that the Save Vector Layer as function permanently changes the CRS for the ...
3 votes
1 answer
71 views

Why QGIS expression display double at concave sections?

I am trying to display the vertices of a polygon with vertex number. In symbology, I have used the Marker line and font marker. . When the Line offset is -5 positive the text 'P7' is displayed far ...
0 votes
0 answers
29 views

Using QgsVectorFileWriter

I have a Python script to load features from a WFS in my QGIS project within a certain buffer. The loading-part of the features works. After that, step 2, I want to save al new loaded feature to an ...
1 vote
2 answers
66 views

Filling field with values from field of another table using QGIS

I am using QGIS 3.28.9. I need to complete a field from a building's layer with the field's values from a plot's layer, based on the location of the buildings. At first I thought of doing it through ...
0 votes
1 answer
279 views

QGIS Server installation (Debian) : error message

I want to install QGIS Server on Debian. I added the official QGIS repository which allowed to install the version of QGIS Server 3.30. For information, the QGIS project that I am trying to serve is ...
0 votes
1 answer
163 views

PyQGIS feature field of type float not setting attribute

I am trying to set a feature in a PyQGIS processing script Its fields are defined like so: interp_fields=QgsFields() interp_fields.append(QgsField('X_int', type=QVariant.Double)) ...
4 votes
1 answer
452 views

QgsTask and thread safety in PyQGIS

I am using QGIS 3.8.2. I subclassed QgsTask in order to process jobs that make class to a postgres database outputs the data as a kmz or shapefile. When I execute the run method directly, everything ...
4 votes
1 answer
1k views

Create dynamic filename, based on attribute value, for output of QGIS model

Basic idea Every user running a model selects a folder where the output of the model, a raster, should be stored as a file. The filename should be created automatically, based on an attribute value (...
0 votes
0 answers
25 views

QGIS Grass Raster import using r.in.gdal.qgis: 'Layer data source could not be found'

I'm a QGIS learner following the official QGIS Training Manual. I'm on Module 12.1. My problem is that when I try to add a raster layer to GRASS using r.in.gdal.qgis, the resulting layer shows a red ...
2 votes
1 answer
186 views

gdalnumeric.LoadFile() with temporary output from QGIS algorithm

I'm trying to access a previously created temporary raster output with gdalnumeric.LoadFile() to calculate some statistics. It seems to me that gdalnumeric.LoadFile() can only access a file through a ...
3 votes
1 answer
2k views

Extract derived data fields from Shapefiles

I've uploaded shapefiles with professionally supplied survey data into QGIS and it all plots fine, then when I export the attributes table into Excel I see that the XYZ values are all zeros. I know ...
2 votes
1 answer
233 views

Setting different symbols for a CSV layer with attribute "Type"

I have a CSV file with columns: Name Latitude Longitude Type (values: Hotel, View) I have this displaying correctly with Name displayed by each point. I would like to have different symbols ...
0 votes
0 answers
85 views

Pretty "buffer" around Point-Layer with as little as possible Vertices [closed]

I'm searching a solution (which I can automate) for getting my Area of Interest around Points of Interest. I've got a point-layer in QGIS. I want to have all the area which is inside a 0.5 m Buffer ...
0 votes
1 answer
64 views

Can't connect with Web Map Services - problem with OpenSSL 3.0.2 Ubuntu 22.04

This problem is connected with Qt5 I believe, starting QGIS from the command line gives, amongst many other messages: Warning: Incompatible version of OpenSSL Warning: QSslSocket: cannot call ...
-1 votes
1 answer
411 views

Ubuntu 16.04 and 18.04 won't install Version 3

sudo apt install qgis installs 2.8 (on 16.04) or 2.18 (on 18.04), but I would like to install version 3 (especially the 3.10 ltr) so I've tried: sudo add-apt-repository https://qgis.org/...
0 votes
0 answers
8 views

Region of Interest selection error in Semi-Automatic Classification Plugin (Error: unable to calculate)

Yesterday I upgraded the Semi-Automatic Classification Plugin. Immediately after doing this, the automatic ROI selection is giving me that error as shown in the attached image. I have tried to ...
0 votes
0 answers
18 views

Calculate default value for field not working in QField but working in QGIS

In QGIS (3.34.3) with an input form I'm assigning as the default value of a field of my buildings polygons the code (codice) from the polygon area to which it belongs, that is stored in another layer, ...
0 votes
0 answers
24 views

Rasterization (Vector to Raster) in QGIS overwrites Maxima values of the vector

I am working on macroseismic intensity maps in QGIS 3.30. My data are in the form of a point vector. In this case, each point has an attribute corresponding to the maximum intensity which was ...
1 vote
1 answer
78 views

QGIS Finding Intersection of Points and Lines Layers in Electricity Grid [closed]

I am new to GIS-related work and am currently using QGIS 3.34 for my research I am trying to find the electricity grid topology and length of power lines between substations in the West of Sweden for ...
1 vote
0 answers
28 views

Using advanced digitizing tools over multiple layers in QGIS

I need to make movements in different layer polygons at the same time (I mainly use move feature and rotate feature tools). I've seen some posts explaining how to do this in multiple steps, but the ...
0 votes
1 answer
883 views

QGIS hidden behind Windows toolbar (bottom)

I'm running QGIS 3.10.6, Windows 10, just downloaded in order to try to alleviate this minor but irritating issue. The bottom of the window of QGIS is repeatedly hiding itself behind the standard ...
0 votes
0 answers
29 views

Not achieving correct pixel width and height for map export in QGIS

Trying to export the full extent of a EPSG:4326 layer of the earth (-180, 180,-90,90) with an exact pixel width (8192) and height (4096). I can't seem to get the width/height correct. If I set the ...
1 vote
2 answers
770 views

Filling in areas between lines with polygons in QGIS

I have to make a geographical map. I have to fill in the gaps between the lines with polygons. Is there a possibility to just trace those lines automatically? I have to do everything manually now, ...
0 votes
0 answers
31 views

Click Functionality Not Working in QGIS Selection Tools

Yesterday, I was using the "select entities by area or single click" tool to select a group of polygons from a shapefile and then using the "change properties of a group of files" ...
2 votes
1 answer
42 views

How to update QGIS display from script run in console

Working from the Python console in QGIS, I am trying to create an 'animation' of sorts by selecting one line after another in a layer with parallel lines, with a pause on each line. I've started from ...
0 votes
0 answers
20 views

Semi-Automatic Classification QGIS Plug-In Error When Running Maximum Likelihood Classifier

I have the following python error when trying to run the Maximum Likelihood classification in Semi-Automatic Classification plugin version 8.2.2 on QGIS 3.28.5. Python version is 3.9.5 File "C:\...
1 vote
1 answer
176 views

QuickOSM Cyrillic UTF-8 importing problem

When I import OSM data by query, the field name_ru is not human-readable, but it is okay in OSM file. Changing the encoding does not help.
1 vote
1 answer
515 views

Pixel size convert from degrees to meters of Martian DEM

I have a Martian DEM whose pixel size is specified in degrees instead of meters. I was trying to convert in Global Mapper but it didn't work. Now I am trying convert in QGIS with projections but it ...
2 votes
1 answer
40 views

Adding geometry from first row of attribute table to all other rows of attribute table of layer using PyQGIS

I have a layer where only the first row in the attribute table has a geometry. I want to copy this geometry to all other rows of the attribute table of this layer but the geometry is still empty. ...
0 votes
0 answers
29 views

QGIS 3.28.5 can't open a project file

Do you know any solution? I think in similar cases I could unzip the .qgz file and then I was opening the .qgs file but I can't do it with this project. I saw other answers, the file is there for ...
1 vote
1 answer
57 views

Why is the extent of a "point" grid different from a "polygon (rectangle)" grid in QGIS?

I cannot find an answer to this question, not even in the official QGIS documentation. Here is the problem: First, I delineate a survey area layer (geometry type is polygon): When I create a grid (...
2 votes
1 answer
52 views

Change selection color to be just a polygon with no fill in QGIS 3

Can we change this to be no fill color but just a yellow outline? Currently stuck in v3.16 but I don't see this in the Dev version either.
2 votes
1 answer
56 views

How to hide or remove the subgroup labels on a QgsLayoutItemLegend with PyQGIS?

I'm trying to build a layout with pyqgis and I'm not able to hide or remove the label from the caption subgroup as shown in the image below. This is what I have until now: ... legend = ...
0 votes
0 answers
24 views

How to automate the code to synchronization postgis live layer on pyqgis?

I possess a dataset stored on a PostGIS server and aim to establish a fundamental synchronization mechanism through code. Although I've implemented the provided code for this purpose, when utilizing ...
0 votes
0 answers
29 views

How to generate CSV file for polygons to show in QGIS

My table looks like this: but adding this as a text defined layer hasn't got me anywhere as X and Y are not clearly defined. I am new to QGIS.
0 votes
0 answers
14 views

QGIS 3.34 and nested GeoJSONs

Is there an issue with how QGIS 3.34 ingests GeoJSONs that were exported by Kili with nested attributes? { "type": "FeatureCollection", "features": [ { "type": &...
6 votes
1 answer
692 views

QGIS 3 doesn't recognize Description from Value Map in attribute table

I have some .csv files that defines Value Maps. When I set them in the Attributes Form panel, it shows the right values and description names according to the .csv files. But as can be seen on ...
0 votes
1 answer
43 views

Using Attribute Table in QGIS [closed]

Can the attribute table of a shape layer be modified as a dynamic table, establishing a list of options and making the work easier?
2 votes
2 answers
145 views

INVALID_CHARACTER_ERR: An invalid or illegal XML character is specified

I have a shapefile. I want to load the shapefile in to QGIS but I am not able to load it. The shapefile is a layer in GeoServer (2.23.2) and loaded into QGIS (3.28.15) vis WFS 2.0.0 connection. QGIS ...
3 votes
1 answer
160 views

QGIS Attribute Form -> Value Relation -> Filter expression: expressions or functions to get the names of current layer and current field

Shortcut to the core question: How to write a custom function to get the name of a field in an Attribute Form? I would like to use it as a variable in a Filter expression of a field with a Value ...
1 vote
1 answer
205 views

How to colour vector tiles based on filter in QGIS 3.16

I have a vector tiles layer that displays fine in QGIS 3.16: A fill without a filter works as well: However, the fill based on a filter on the feature properties does not work (result can be seen in ...
1 vote
1 answer
46 views

Make statistical expression for field calculator

I have a vector layer called 'Stations' and a table called 'Attitude' and a relation exists between the table's ('Attitude') "Staion_id" field and vector layer's ('Stations') "uuid"...
0 votes
1 answer
100 views

Removing intermediate layers in processing script

I am creating a processing plugin in QGIS that has two steps. Write features to a FeatureSink. Convert the FeatureSink to a layer and perform native:joinattributesbylocation. I am using the QGIS ...
1 vote
1 answer
51 views

Select by location fails for some lines in QGIS

I have many line objects in a layer called "line" (pink). Further, I have line objects in a layer called "Connection" (blue). The lines in "Connection" are created by the ...
0 votes
1 answer
244 views

PyQGIS save a project and close a project - QGIS v3

Using PyQGIS with QGIS v3 My script opens an empty QGIS project (thinking this would retain the path). I add some layers, perform a few tasks. All is good. Now I want to close the project or I should ...
0 votes
1 answer
174 views

QGIS - QGIS2WEB - Leaflet - CSS Code - Changing background colors [15.09.22]

I am using the QGIS2WEB plugin within QGIS 3.0. I have selected "Leaflet" for export. I am trying to use a different background-color than the normal white (#fff) that appears in the ...
1 vote
1 answer
269 views

Adding new provider to QgsProviderRegistry.instance().providerList() using PyQGIS

I'm trying to get vector layer from arcgisfeatureserver in a standalone app, didn't work, so I checked what providers I got on PyCharm: ['gdal', 'memory', 'mesh_memory', 'ogr', 'vectortile'] While in ...
3 votes
1 answer
569 views

Getting results from processing.run GRASS r.resample in PyQGIS

I am trying to get output from r.resample in a stand-alone PYQGIS application. The code runs and does not show any errors, but it does not save an output file (i.e. 'c:/path/to/output.tif'). As far as ...

1
2 3 4 5
88