I have been working on a number of changes and new features for the Alternative Colors map style (AC-Style) during the past few months (more on that likely in future blog posts) and during that time have also contemplated quite a bit about the situation of open map design – in general and in the OpenStreetMap community specifically. One outcome of these considerations is that i have decided to change the license of the style. And in this blog post i want to explain why.
Rule based map design is something of an unusual concept – both for those who come from and who look at things from a perspective of traditional IT and software development, as well as for people with a traditional graphics design, visual art or cartography background. A map style like OSM-Carto or the AC-Style contains rules on how geodata is transformed into a visual representation – the map. These rules are implemented in the form of code that is automatically processed by computers. Hence many software developers (and sometimes also traditional designers) have a tendency to view map styles as software and to reduce them to being software. The main problem with that (apart from dismissing the core of map design work itself as insignificant) is that the way map styles work clashes with the classic paradigm of computer programming that software processes data and that the two things are technically and legally separate. Past conversations i have had about copyright and licensing of map design have often shown that many people working in IT firmly believe that when you process data with a computer program the copyright of the processed data is categorically unaffected by the copyright of the computer program. That there are such things as self replicating programs – challenging this idea quite clearly – is typically considered a practically irrelevant special case.
The map produced by an automated rule based map style, however, is a derivative of both the geodata the style is applied to and the style itself. The resulting map obviously does not contain the generic logic of the map style any more, but it contains the work of the map designers who developed the style – in the form for example of carefully balanced color combinations or line signatures – or just in the selection of what to show and what not to show at a certain map scale. And these choices are actually manifested in the resulting map. Hence the rendered map is not only based on the map style and the work of its developer in the same sense as a computer program generating data according to the intentions of its programmer, it directly and literally contains the design work itself. Or in other words: You could call it a collage of the work of the mapper generating the geodata and the work of the map designer writing the style rules.
In light of this it is rather curious that most openly licensed map styles either waive all rights of their designers (like with CC0) or are licensed under a software license (usually a fairly liberal one like BSD or MIT). This is especially remarkable in the context of OpenStreetMap, where the work of the mappers is subject to the significantly more substantial terms of the ODbL.
Superficially this makes it easier to deal with the peculiar nature of map styles as works subject to copyright. But i doubt, meanwhile, that in the long term this actually provides a net benefit. I have pointed out on this blog on several occasions now that i think in the OSM-Community (and probably also in geodata processing and digital map production in general), intellectual work, and that of course in particular means map design work, is severely undervalued compared to technical work and that this substantially limits innovation in the domain. That most open map design projects in this context are licensed in a way that allows the users of the map styles to pretend they are just software seems quite clearly not helpful in that regard.
One specific observation that made this abundantly clear was that when i pointed out to the board of the OpenStreetMap Foundation back in mid 2022 that it would be nice and morally advisable if the OSMF as the largest user of OSM-Carto would acknowledge the work of the OSM-Carto designers in their public communication, in particular on the website where the map is shown – nothing happened. And why should it you could say. If the OSM-Carto designers really would want this kind of acknowledgement they could require that in their license. And since as is this is legally not required – why should the OSMF provide it?
One important prerequisite to change the way the OSM community looks at map design work quite clearly is to provide some practically straightforward options to map designers how they can license their work in a way that
- ensures that the style and other map design work derived from it remains open and can be used under similar terms.
- properly acknowledges and deals with the special nature of rule based map design as something that has both software components and contains visual design work that is included in the produced maps.
- requires users of the design work to acknowledge and credit the work of the map designers developing the style.
This is not easy because there so far seem to be no licenses specifically developed for map styles. What helps, however, is to look at other domains where the situation is similar. Economically significant here is in particular the field of computer games where – in a similar fashion as in map design – you have a combination of visual design work and software development that gets exposed to the user in the form of a collage. License models that are used in that context could therefore be suitable for map style licensing as well.
The choice i have made for the AC-Style is to license the visual design components under CC-BY-SA 4.0 and the software elements under AGPL 3.0. Both CC-BY-SA and AGPL have in the past been used in map design contexts – CC-BY-SA notably in the OpenTopoMap project, the AGPL for example for the transliteration work of Sven Geggus. Practically those licenses mean that you have share-alike provisions for both the software and the design components and that deployments of the style or derivatives need to release any modifications of the style rules under compatible terms (which would not be the case with the GPL). If this is practically a good choice of licenses will remain to be seen – like the style itself the license can be considered experimental.
Having the two different licenses for software components and visual design work does not mean that you can flatly assume that all parts written in a programming language are only subject to the AGPL. As i have tried to point out above this is not merely a technical distinction. There are plenty of cases in the style where visual design is implemented in the form of code – see the symbol designs for trees that are represented in the form of SQL code for example.
That i license the AC-Style under this license scheme does not mean that the features and ideas i develop in the style cannot also make it into OSM-Carto any more. So far i am the sole author of the specific features of this style and i am free to also license parts of this work under a different license if i choose to. On the other hand, it might of course be a good idea to discuss if to change the license of OSM-Carto as well. As i have discussed above, it is meanwhile fairly doubtful if the choice of a very liberal license for an open community map design project like OSM-Carto is of benefit for progress and innovation in the field and for attracting competent designers to contribute to the project.
I am, however, also aware that moving to a license more limiting for the style user is not necessarily going to widen the user base of the style. The whole initiative to change the license is part of a long game to raise awareness that rule based map design is not just a somewhat specific type of software development but a field of value and importance on its own that depends on qualified and talented designers being motivated to invest their time and energy in it.
I also want to make clear that this license change is not meant to diminish the work of the OSM-Carto contributors whose work the AC-Style is based on. Therefore i ask – for the attribution as required by the new license – to specifically also acknowledge their contributions.
The main result i hope for is that this initiative encourages other map designers to (a) embrace the idea of open map design and (b) to make more conscious and self determined choices about the terms under which they make their work available to others. Right now, unfortunately, too many map designers – when working on rule based map design – happen to publish their work not under terms of their choosing but under ones that others (who are often not map designers) have picked. Or they keep their work proprietary because they cannot find a good way to make available and share it and to not at the same time make it available for selfish exploitation by others without giving anything back.