Tag: processing

During the pandemic, people noticed how well they could work remotely, how productive meetings via video call could be, and how well webinars worked. At OPENGIS.ch, this wasn’t news because we have always been 100% remote. However, we missed the unplanned, in-person interactions that occur during meetups with a or . That’s why we’re very pleased that last week we could join the Swiss QGIS user day for the second time after the pandemic.

OPENGIS.ch has been invested in QGIS since its inception in 2014, actually even before; our CEO Marco started working with QGIS 0.6 in 2004 and our CTO Matthias with version 1.7 in 2012. Since 2019, we have also been the company with the most core committers. We can definitely say that OPENGIS.ch has been one of the main driving forces behind the large adoption of QGIS in Switzerland and worldwide. 

Looking at the work done in the QGIS code we’re by far the most prolific company in Switzerland and second worldwide only to North Road Consulting. On top of it, we were the first – and still only one of two- companies to sustain QGIS.org at a Large level since 2021.

This makes us very proud and it is why we’re even happier to see how much that is happening around QGIS in Switzerland aligns with the visions and goals we set out to reach years ago.

The morning started with a presentation by our CTO Matthias “What’s new in QGIS” featuring plenty of work sponsored by the Anwendergruppe CH.

DXF Improvements, the release of SwissLocator 3.0 with swissalti3d and vector tiles integration, and an update on the advances towards solid curve handling in QGIS, a prerequisite for properly handling AV data in Switzerland, were only some of the many noteworthy points he touched.

The highlight of Matthias’ presentation was the better OGC API Features support in QGIS, which was also highlighted in a subsequent talk about Kablo, showing how the next generation of industry solutions (Fachschalen) will be implemented.

Slides: Neues aus der QGIS Welt - QGIS Anwendertag 2024

Following was a short presentation on the project DMAV, Christoph Lauber introduced a project that aims to implement an industry solution for official cadastral surveying with QGIS.

Adrian Wicki of the Federal Office for the Environment (FOEN) and Isabel presented how OPENGIS.ch and the partners Puzzle and Zeilenwerk help the FOEN with the SAM project with assess the hazards of flood, forest fire, or landslides, and warn authorities and the population. With an agile project organisation, the complex project succeeds in fulfilling requirements by applying user-centred development concepts. QGIS is used for visualizing and analyzing data and helping forecasters gain insights into the current situation.

Slides: BAFU_SAM

Andreas Neumann from ETH Zurich and Michael presented the qgis-js project. QGIS-js is an effort to port QGIS core to WebAssembly so that it can be run in a web browser. Although still in the early experimentation phase, this project has great potential to leverage interesting new use cases that weren’t even thinkable before.

Slides: https://boardend.github.io/qgis-js-demo/ 

Olivier Monod from the City of Yverdon presented Kablo, an electricity management proof of concept of the next generation implementation for industry solutions developed in collaboration with OPENGIS.ch.

By applying a middleware based on OGC API Features and Django, Kablo shows how common limitations of current industry solutions (like permission management and atomic operations) can be overcome and how the future brings desktop and web closer together.

Slides: kablo-qgis-user-days

Obviously, it wasn’t just OPENGIS.ch. Sandro Mani from Sourcepole presented the latest and greatest improvements on QWC2, like street view integration and cool QGIS features brought to a beautiful web gis. Andreas Schmid from Kt. Solothurn presented how cool cloud-optimized geotiff (COG) is and what challenges come with it. Interested in the topic? Read more in our report about cloud optimized formats. Mattia Panduri from Canton Ticino explained how they used QGIS to harmonise the cantonal building datasets and Timothée Produit from IG Group SA presented how pic2map helps bring photos to maps. 

To round up the morning, Nyall Dawson from North Road Consulting did a live session around the world to show the latest developments around elevation filtering in QGIS.

In the afternoon, workshops followed. Claas Leiner led a QGIS expression one while Matthias and Michael showed how to leverage QGIS processing for building geospatial data processing workflows. 

The first QGIS model baker user meeting took place in the third room. The participants discussed this fantastic tool we developed to make INTERLIS work smarter and more productive.

It was a very rich and constructive QGIS user day. We came home with plenty of new ideas and a sense of fulfilment, seeing how great the community we observed and helped grow has become.

A big thanks go to the organisers and everyone involved in making such a great event happen. Only the beer in the sunshine was literally watered by the rain. Nevertheless, there were exciting discussions in the station bistro or in the restaurant coaches on the way home.

See you next time and keep contributing

It’s been a long time since I last blogged here. Let’s just blame that on the amount of changes going into QGIS 3.0 and move on…

One new feature which landed in QGIS 3.0 today is a processing algorithm for automatic coloring of a map in such a way that adjoining polygons are all assigned different color indexes. Astute readers may be aware that this was possible in earlier versions of QGIS through the use of either the (QGIS 1.x only!) Topocolor plugin, or the Coloring a map plugin (2.x).

What’s interesting about this new processing algorithm is that it introduces several refinements for cartographically optimising the coloring. The earlier plugins both operated by pure “graph” coloring techniques. What this means is that first a graph consisting of each set of adjoining features is generated. Then, based purely on this abstract graph, the coloring algorithms are applied to optimise the solution so that connected graph nodes are assigned different colors, whilst keeping the total number of colors required minimised.

The new QGIS algorithm works in a different way. Whilst the first step is still calculating the graph of adjoining features (now super-fast due to use of spatial indexes and prepared geometry intersection tests!), the colors for the graph are assigned while considering the spatial arrangement of all features. It’s gone from a purely abstract mathematical solution to a context-sensitive cartographic solution.

The “Topological coloring” processing algorithm

Let’s explore the differences. First up, the algorithm has an option for the “minimum distance between features”. It’s often the case that features aren’t really touching, but are instead just very close to each other. Even though they aren’t touching, we still don’t want these features to be assigned the same color. This option allows you to control the minimum distance which two features can be to each other before they can be assigned the same color.

The biggest change comes in the “balancing” techniques available in the new algorithm. By default, the algorithm now tries to assign colors in such a way that the total number of features assigned each color is equalised. This avoids having a color which is only assigned to a couple of features in a large dataset, resulting in an odd looking map coloration.

Balancing color assignment by count – notice how each class has a (almost!) equal count

Another available balancing technique is to balance the color assignment by total area. This technique assigns colors so that the total area of the features assigned to each color is balanced. This mode can be useful to help avoid large features resulting in one of the colors appearing more dominant on a colored map.

Balancing assignment by area – note how only one large feature is assigned the red color

The final technique, and my personal preference, is to balance colors by distance between colors. This mode will assign colors in order to maximize the distance between features of the same color. Maximising the distance helps to create a more uniform distribution of colors across a map, and avoids certain colors clustering in a particular area of the map. It’s my preference as it creates a really nice balanced map – at a glance the colors look “randomly” assigned with no discernible pattern to the arrangement.

Balancing colors by distance

As these examples show, considering the geographic arrangement of features while coloring allows us to optimise the assigned colors for cartographic output.

The other nice thing about having this feature implemented as a processing algorithm is that unlike standalone plugins, processing algorithms can be incorporated as just one step of a larger model (and also reused by other plugins!).

QGIS 3.0 has tons of great new features, speed boosts and stability bumps. This is just a tiny taste of the handy new features which will be available when 3.0 is released!