Tag: en_gb

We’re genuinely excited to co-organise the upcoming QGIS User Conference together with QGIS User Group Switzerland, and to do so in Laax, right here in the Swiss Alps.

Laax is home to OPENGIS.ch and the place where QField was born. It is a setting that has shaped how we work, how we collaborate, and how we think about building open-source tools that are meant to be used in the real world.

Bringing the global QGIS community together in such a place feels just right. People and ideas come together around open source, with space to exchange, reflect, and collaborate, in an environment that mirrors values that are deeply rooted in our DNA and our close connection to nature.

• Yes, the venue is reached by cable car
• Yes, it comes with breathtaking views
• And yes, there will be plenty of opportunities to hike, bike, fly, or simply enjoy great conversations

The mountains will not just be a backdrop. They will be part of the conference experience.

As Marco, our CEO and Chair of QGIS.org, puts it:

“I’ve never been more excited about a QGIS conference location announcement. Welcoming the community to my hometown in the Swiss Alps feels very special. This is where OPENGIS.ch is based and where QField was born, and it is a perfect place for meaningful exchanges and shared experiences.”

We’re very much looking forward to organising this conference and to welcoming the QGIS community to Laax for what we hope will be a memorable and inspiring QGIS User Conference.

Updates and details can be found at conference.qgis.org

Sorry, this entry is only available in French.

Finally it’s here: Jupyter notebooks inside QGIS. I don’t know about you but I’ve been hoping for someone to get around to doing this for quite a while.

Qiusheng Wu published the first version of the Notebook plugin on 26 Dec 2025. Late Christmas present?!

For the setup, there’s a handy tutorial by Hans van der Kwast and, additionally, Qiusheng published an intro video:

Development is going fast (version 0.3.0 at the time of writing) so there will be new features when you install / update the plugin compared to both the tutorial and the video.

The user interface is pretty stripped down with just a few buttons to add new code or markdown cells and to run them. And there is a neat drop-down menu with all kinds of ready-made code snippets to get you started:

For other functionalities, for example, to delete cells, you need to right-click on the cell to access the function through the context menu. And, as far as I can tell, there is currently no way to rearrange cells (moving them up or down).

I also haven’t quite understood yet what kinds of outputs are displayed and which are not because – quite often – the cell output just stays empty, even though the same code generates output on the console:

Some of the plugin settings I would have liked to experiment with, such as adjusting the font size or enabling line numbers, don’t seem to work yet. So a little more patience seems to be necessary.

I’ll definitely keep an eye on this one :)

The journey continues: QgsArrowIterator is now merged! This makes it possible to iterate over QgsFeatures as Arrow batches.

This is where we are now, quoting Dewey Dunnington:

import geopandas
from nanoarrow.c_array import allocate_c_array
import qgis
from qgis.core import QgsVectorLayer

# Create a vector layer
layer = QgsVectorLayer("tests/testdata/zonalstatistics/polys.shp", "layer_name", "ogr")
schema = qgis.core.QgsArrowIterator.inferSchema(layer)

it = qgis.core.QgsArrowIterator(layer.getFeatures())
it.setSchema(schema, 1)

c_array = allocate_c_array()
schema.exportToAddress(c_array.schema._addr())
it.nextFeatures(5, c_array._addr())

print(geopandas.GeoDataFrame.from_arrow(c_array))
#> lev3_name                                           geometry
#> 0    poly_1  MULTIPOLYGON (((100.37934 -0.96049, 100.37934 ...
#> 1    poly_2  MULTIPOLYGON (((100.37944 -0.96044, 100.37955 ...
#> 2    poly_3  MULTIPOLYGON (((100.37938 -0.96049, 100.37949 ...

print(geopandas.read_file("tests/testdata/zonalstatistics/polys.shp"))
#> lev3_name                                           geometry
#> 0    poly_1  POLYGON ((100.37934 -0.96049, 100.37934 -0.960...
#> 1    poly_2  POLYGON ((100.37944 -0.96044, 100.37955 -0.960...
#> 2    poly_3  POLYGON ((100.37938 -0.96049, 100.37949 -0.960...

Further improvements are already being planned. To quote from the ticket:

“The final state after this improvement would be a compact way for Arrow Python consumers like GeoPandas to ergonomically consume a layer. Maybe:

geopandas.GeoDataFrame.from_arrow(qgis_layer_object)

Or maybe:

geopandas.GeoDataFrame.from_arrow(qgis_layer_object.getArrowStream())

Looking forward to seeing this develop further.

Credits : Bru-nO (Pixabay Content License)

Thanks to funding from the Bordeaux Metropolis, I had the chance to work on CMYK (Cyan Magenta Yellow blacK) support in QGIS. The metropolis’ goal is to remove the last barrier preventing their complete migration from ArcGIS to QGIS.

The developments are now complete and will be available in QGIS version 3.40, scheduled for release in October 2024, before becoming the next LTR in February 2025. It should be noted, however, that CMYK support will only be complete in QGIS versions built with Qt 6 (still unofficial version) for reasons explained in the article. On Windows, this version can currently only be installed using OSGeo4W (qgis-qt6-dev version).

EDIT: Actually, QGIS version built with Qt 6.8, which ships the needed modifications for CMYK PDF export, is not yet released. More information here.

What is CMYK?

You probably know RGB, which allows you to code a color on screen by choosing the amount of red, green and blue in that color. You may also use TSL or TSV.

RVB – Credits : Daniel Roberts (Pixabay Content License)

These 3 color references allow a color to be coded for a screen, while CMYK targets printers by allowing to set the exact quantity of ink that will be released during printing (hence the 4 CMYK components, one per ink cartridge).

CMYK ( here from left to right KCMY ) – Credits : Magnascan (Pixabay Content License)

The characteristics of CMYK differ greatly from RGB, it’s considered a subtractive colorimetric mode, because the ink absorbs light unlike RGB which is said to be additive, the more red, green, blue you have the closer you are to full light, white.

The intrinsically different nature of these 2 color spaces means that it is strongly advised not to convert from one to the other. The best is to choose a color in a space (CMYK for printing, RGB for rendering on screen) and stick to it.

Worse, printing the same color is different depending on the printer, ink, paper… The choice of a CMYK color has to be done in a color space, represented by a ICC profile file, provided by your printer. It is a bit like a color chart used when choosing paint.

Now you can argue about the REALLY good color of a road line – Credits : Yanis Ladjouzi (Pixabay Content License)

Developments in QGIS… and Qt

It is now possible in QGIS to:

• Enter colors in CMYK format, and in floating precision;
• Define your preferred color mode (RGB or CMYK) and your color space;
• Generate a file in PDF/X-4 format (ready for printing) embedding a color space and using CMYK colors;
• Allow the expression engine to manipulate CMYK colors without converting them to RGB;
• Manage CMYK color ramps;
• Lots of other small improvements and corrections about color management.

Selecting colors in QGIS in CMYK

The beautiful story of Open source

I took great pleasure in participating in this development because it is the result of the collaboration of many players in free software.

During a first phase of study concerning the support of CMYK in QGIS, we quickly identified that Qt, the framework used by QGIS for rendering maps, has limitations. It converts all colors to RGB when rendering maps in PDF format and its support for CMYK color spaces is incomplete.

It is therefore necessary to make it evolve. We therefore turn to our preferred partner when it comes to Qt, KDAB, and more precisely Giuseppe D’Angelo who then carries out the necessary developments.

Regarding new features, these are only available in Qt 6 (Qt 5 is end of life). This is why CMYK support is incomplete in official versions of QGIS still based on Qt 5.

QGIS.org, the association that oversees the QGIS project, decided to fund the developments on Qt. Oslandia, on the other hand would have to manage these developments and then to carry out the integration in QGIS. This integration as well as the related new features was funded by the Bordeaux metropolis.

My developments were then reviewed by other QGIS contributors. (If you want to know more about the QGIS contribution process, you can read a previous blog post about software quality in QGIS)

Finally, I wanted to give a special thanks to Jehan, developer on the GIMP project. His availability and thoroughness in our mail exchanges greatly helped me understand the technical and functional issues of CMYK, and most certainly contributed to the quality of the result.

Next

QGIS 3.40 will therefore be able to generate a PDF/X-4 file using CMYK colors. Qt, for its part, improves CMYK support, PDF writing, and color space management.

Thanks again to the Bordeaux metropolis and QGIS.org for funding these developments, and all the people involved in their realization.

We would be delighted to have feedback from users on your use cases related to color management in QGIS. Do not hesitate to write to us or comment on our posts to tell us how you use these features.

These foundations in the management of color spaces in QGIS open the door to future improvements. If you are interested in this topic and would like to contribute, please contact us at infos+qgis@oslandia.com and check out our QGIS support offer.