Stadtgrün is the department that looks after the greenery of Winterthur Municipality. As the city lies on the Swiss Plateau, in a basin ringed by wooded hills, the department has a broad area of authority: forests and landscape, parks and gardens, the city's tree stand, and the municipal cemeteries. Within that, Samuel Schweize manages forest and landscape, which covers forest planning, tree management, roads and construction in the forest, and protecting residents from landslides. He also ends up being the informal IT support for his section, which is how he came to be the person developing and managing all of their Mergin Maps projects.
Samuel joined a year ago and found Mergin Maps already in place, introduced by his predecessor about a year before that. His background is forestry rather than GIS, with some QGIS experience from his studies at BFH in Bern. Today around 35 colleagues have editing access to roughly fourteen projects, hosted on the city's own server.
Two jobs where the map decides the order of operations
Salvage logging after a storm is the clearest example of what the setup is for. Once the wind has passed, someone has to establish where the dead and damaged trees are, get chainsaw crews and machine operators to the right places, and decide where the logs will be stacked for collection. Tree type is also part of the record. Conifers need a quick response, because standing deadwood invites bark beetles and nobody wants to help that population along. Broadleaves can wait a little longer. Having that distinction on the map, attached to a location, is what highlights which parts of the work need to be prioritised, instead of operating in the blind.
Salvage logging (Holzerei) project in Mergin Maps
The invasive plant project is the one that reaches the widest group. Everyone in the department has Mergin Maps on their phone, and anyone who comes across a stand of an invasive species can record it on the spot, using a simple drop-down form. Symbology plays an important role. Points are coloured by species and sized by the extent of the infestation, so the map reads at a glance. Once an area has been cleared, the fill is removed and a transparent circle stays behind, which keeps the history visible: you can still see that something was there a year or two ago, without it competing for attention with the sites that still need work.
That project serves another purpose. Government funding is available for invasive species control, and a claim needs to show how large the affected area was and what was done to treat it. A set of mapped points with attributes attached is exactly the kind of evidence that supports a claim, and it comes out of work the team was doing anyway.
Invasive species (Neophyten) project in Mergin Maps
The rest of the portfolio
Other projects are smaller but follow the same logic. A bench inventory records the type and condition of benches across the forest areas. A watercourse project maps the small rivers that the department is responsible for maintaining, along with parcel ownership, so that crews going out know which stretches belong to the city and which are private before they start work.
There is also an assessment project that goes beyond collection. Samuel set up around 70 circular sample plots, roughly an acre each, which the team surveyed for indicators such as standing deadwood and micro-habitats on trees, feeding a biodiversity index. The analysis itself happens afterwards in Excel, R and Python. As he points out, the survey could have been done on paper, but finishing the field day with one structured file rather than a stack of forms is where precious time is saved.
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A clear overview from a simple interface
Asked what the main advantage is, Samuel does not reach for anything dramatic. It is the overview. He knows what is happening outside without having to be told, and colleagues in the office can see what has been done. Crews no longer need to call him to ask where a particular tree is, because a point with a short description tells them where to go and what to do when they get there. Before this, the work ran on paper maps marked up with highlighters and pencil, handed to whoever was planning the job. The change is less about faster fieldwork than about the department having a shared picture of its own territory.
That picture only holds together if people actually open the app. Most of the field crew are not interested in software: they work outdoors and they are not very fond of doing anything important on a phone. What made Mergin Maps stick was its simple UI that does not ask much of them. There are not a lot of buttons, and not a lot of options to choose from. Samuel, meanwhile, keeps finding features he did not know were there, which is the balance he needs: he learns as he works with Mergin Maps.
What comes next
The bench inventory is due to extend from the forest areas into the city itself, which means bringing a new group of colleagues into the workflow. Beyond that, Samuel is working towards connecting Mergin Maps with municipal data sources and with swisstopo, though the city's IT rules and the key-based access those services require have made that harder than expected so far.
None of this is a complicated deployment, and that seems to be the point. One person builds the projects, 35 colleagues use them at whatever frequency their job demands, and the maps quietly do the coordinating. If that sounds like the shape of the work you are trying to organise, we are always glad to hear about it.
