r/QGIS

On Ubuntu, I was trying to run a script written for py3.14, but that failed with:

ImportError: cannot import name 'StrEnum' from 'enum' (/usr/lib/python3.10/enum.py)

Question: if one is comfortable compiling a python interpreter from source, is it generally safe to build QGIS from source as well? Asking to avoid a rabbit hole.

Otherwise, thanks for the product and your time.

Tried to point to a newer installation...

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USE_PY=/home/smitty1/.local/share/uv/python/cpython-3.14.0-linux-x86_64-gnu/bin/python3.14

export PATH=$USE_PY:$PATH

qgis &

...but that was also rejected:

===

Couldn't load SIP module.

Python support will be disabled.

[stuff]

QGIS died on signal 11

REALLY BAD FIX:

===

This appears to be working well enough for my little script, but is clearly not what you want to do in the Real World:

from enum import Enum as StrEnum #appease QGIS

Did the first LTR utilizing QT6 (4.0 and above) drop today or am I reading the roadmap wrong?

Hello I need help

Can someone tell me how to filter osm/openstreetmap river shp data based on order? I'm working on Southeast Asian map and want to filter out the smallest rivers out of the map. Thank you!

Today I used for the first time qgis and I was impressed!

In my work I don't have much use for extremely accurate mapping tool, I could get by with a screenshot from Google Earth and maybe a pin to identify location, just eyeballing it.

And today I was doing just that, I had to eyeball the location of some small electrical box and conduit by crossreferencing an old electrical schematics, handdrawn, of a railway station. To make sense of it I started to trace the railways and railway switch which were recognizable enough.

But Google earth web started freezing constantly, working on it was impossible. So I searched for a desktop mapping tool.

I was aware of qgis, I already heard talking about from colleagues, but never used before. I imported the kml file of what I've done so far in Google Earth and ready to start tracing.

Not really though, since I had to load the map layer first. So I load both the satellite view and the open street map one. I discover I can overlap the 2 map and give a transparency to one later so both would be visible. What I want to see is mainly the satellite view, but I can see that the railways in the open street map are quite accurate, but the rest of the open street is a bit distracting for my purpose.

So I wonder if can filter only the railways line from the map? Of course I can!

Just install a plug in, and a do a quick query filtered per key: railways. Perfect line tracing, that I can style like I want.

Mind you, using the kml file trip me over: apparently is not a nice format to save edits, so I had to redo work because it got lost after saving. And I spent way more time that I should have to tinker with this or that style. But what a more satisfying experience than manually tracing lines.

What a powerful tool! The future is full of automation possibilities. And it's open source!

Have been joining monthly data CSV file to a geo-referenced CSV location file. This has worked pretty well in the past for smaller files but today I have attempted to enter 12 months worth of data (4459 points) so I can do a temporal but it just freezes up for about 20 minutes.

My steps are.

1. Load the Post Code (PC) CSV (18500 points) and then hide the points (just to reduce clutter).

2. Load Data CSV as a no reference text layer.

3. On PC layer, Properties, Join and select Data layer and match the two postcode fields.

4. Join the Data fields

5. On PC layer, right clink and filter to make a virtual layer and add an argument Postcode = Postcode AND Suburb = Suburb AND State = State (method to the madness as we have some towns/suburbs the same in other states so found this the best way to filter out duplicates of wrong data).

6. Save filtered virtual layer as a geopackage.

Is there a better way to join, or is this the simplest method?

Thanks.

G'day team,

Wondering if there is an alternative to Klas Karlsson's Layout Loader plugin. I have not seen him post in a long time so do not think he is doing any QGIS work now. I found it a very useful plugin in ver 3.**, so was hoping there was an alternative out there in the wild.

Hi, I was wondering if I could get some help. I was working on a project and editing a layer. When I finished and clicked the save layer button (not the save project), it dissapeared.

The layer still shows on the layers panel, but it seems the file is empty - not only the changes that I made, but the original shape.

Can anyone tell me why did this happend and how to fix it? Is there anyway that I can recover the changes I made?

I'm currently working on a research project on LULC classification of Aizawl district (Mizoram, India) using Sentinel-2 Surface Reflectance (10 m), DEM, slope, aspect, spectral indices (NDVI, NDBI, MNDWI, NDRE), and Random Forest/XGBoost. My goal is to publish this work, so I'm trying to build a methodology that is scientifically robust rather than simply achieving high accuracy.

I'm facing several issues and would really appreciate guidance from anyone experienced in remote sensing or Earth Engine.

Current workflow
Sentinel-2 SR (10 m)
Dry season composites (Nov–Feb)
Median composite
Cloud masking
Features: Sentinel bands + DEM + Slope + Aspect + Spectral Indices
Classes: Dense Forest, Open Forest, Agriculture, Barren Land, Water Bodies, Urban
Issues I'm facing

1. Temporal generalization
Should I:

Train separate models for 2017, 2020, and 2025 and compare LULC changes?
Or combine training samples from all three years into a single model and evaluate whether it generalizes across time?

Has anyone successfully built a single Sentinel-2 model that performs well across multiple years?

2. Composite quality / tile seams

Some areas of my Sentinel-2 composites appear faded or radiometrically different, especially near what seem to be Sentinel tile boundaries. These areas often lead to incorrect classifications.

Is this expected when using median composites?
Would you recommend Quality Mosaic, Medoid, or another compositing strategy instead?
Is there a better cloud-masking workflow than the standard QA60/SCL approach?

3. Training sample collection

I'm using:

Sentinel false-color composites in QGIS to digitize Dense Forest and Open Forest.
Google Earth Pro historical imagery to identify Agriculture, Urban, Water, and Barren Land where they're easier to distinguish.

Is this considered an acceptable sampling methodology for a research paper, provided all samples correspond to the same time period?

I'm looking for advice from anyone who has worked on multi-temporal Sentinel-2 classification, Earth Engine, or remote sensing research.

If you've published work in this area or have practical experience, I'd really appreciate your suggestions or even a discussion. I'm still early enough in the project to improve the methodology before writing the paper.

Hello all,

I've been using Qgis for some time now and I'm learning how it works. I'm having obstacles on a daily basis but I managed to resolve them.

However, there is one very annoying issue that keeps repeating and I don't know how to avoid it - sometimes labels just disappear. I don't know what I did to make it happen as it is a random occurrence. One way I found to resolve this issue is to start drawing a feature (line or surface) and I don't need to finish it, just get to the dialogue to add attributes, cancel new feature and labels return. This works most of the time, but it doesn't always help.

Sometimes labels re-appear when I finish editing a layer, but it's also inconsistent. I wanted to recreate this manually to follow the logic and avoid this, but it's very hard to reproduce. I hope someone had the same issue and managed to resolve it. I can't present this bug if I can't reproduce it.

I have used previous version of QGIS and had the same issue. I thought with an update this will be resolved, but no. For compatibility issues, I cannot yet switch to 4.0 or higher version.

I've searched the issue on the web, but haven't found the same one I have. Partly because web search has gone to hell and AI has taken over or I'm getting out of touch with current generation of internet - both are possible.

Has anyone got any idea what is going on and how can I avoid it?

Info:
- QGIS version 3.44.7-Solothurn
- QGIS code revision ea262bc5ed8

Libraries
- Qt version 5.15.13
- Python version 3.12.12
- GDAL version 3.12.1 — Chicoutimi
- PROJ version 9.7.1
- EPSG Registry database version v12.029 (2025-10-03)
- GEOS version 3.14.1-CAPI-1.20.5
- SQLite version 3.50.4
- PDAL version 2.9.0
- PostgreSQL client version 17.3
- SpatiaLite version 5.1.0
- QWT version 6.3.0
- QScintilla2 version 2.14.1
- OS version Windows 11 Version 2009

Active Python plugins
- basemaps 2.1
- ContourLines 1.2.1
- qfieldsync v4.22.3
- db_manager 0.1.20
- grassprovider 2.12.99
- MetaSearch 0.3.6
- processing 2.12.99

TIA

EDIT: forgot to mention that labels disappear independently of the zoom level.

hello everyone, i am a rookie GIS user, primarily working in architecture field and have been using other software for 3D and CAD.

I have a question about backing up QGIS project, is it easy and straightforward? can i just copy and paste the folder and its related files into the new directory and then I could still all layers with their different styles and colors?

I am also backing up my mac using Time Machine and will transfer to my new mac, but just afraid that i will lose that distinct layers and styles. It took me weeks to set that upz

any advices or answers are welcome :) thank you

On QGIS, I am working on a project based on a complex path system. For this project, I am using points that are associated with a first segment of the path system. Each point has a flow (or “traffic volume”). I want to find a way to associate each point with a road network up to the main path (multiple main path option), keeping the segments separate, while ensuring that the flow of the point is assigned to the segment it uses.

Example: The first point has a flow of 20, and the second point has a flow of 30. If they use the same segment, I want that segment to have a total flow of 50.

Does anyone have a solution or approach to help me achieve this? Thank you very much!