Fractal is rich and scalable map style based on the OpenStreetMap (OSM) geo data model. Cartography rules are written using CartoCSS syntax and the actual map is generated by Mapnik as a rendering backend.
Fractal is a general purpose style, but it's exploiting the possibilities of high zoom levels (z18+) and aims to support so called "micromapping". It will be probably less usable for rural and outdoor areas, where almost all the objects are important and should be amplified to be visible. On the other hand, urban areas filled with lot of POIs should be less cluttered, because objects are moved to the corresponding zoom levels according to their size, and at the same time showing more objects, because high zoom levels can fit more. In particular, zoom level 20 (z20) can contain a lot of useful details, not included in other map styles.
You need a PostGIS database populated with OpenStreetMap data along with auxillary shapefiles. See INSTALL.md.
The shortest way to start is probably to deploy a Docker container, which allows to easily preview the changes.
If you want to run a production server using Fractal, look at the tutorials at Switch2OSM and follow the instructions. Just remember to change the repository address and directory name when needed.
Contributions to this project are welcome, see CONTRIBUTING.md for full details.
Please follow Code of Conduct when interacting with other people.
General guidelines are outlined in CARTOGRAPHY.md. It should give you the idea about different aspects of the project, however this is not a rule book.
These stylesheets can be used in your own cartography projects, and are designed to be easily customised. They work with Kosmtik and also with the command-line CartoCSS processor.
Currently text labels in Fractal are rendered using "name" field, which holds the common names used on a given area. If you want to apply different language rules, check the l10n data preprocessor from German style.
This project follows a common MAJOR.MINOR.PATCH versioning scheme (semantic versioning). In the context of a cartographic project you can expect the following:
- PATCH: When a patch version is released, there would be no reason not to upgrade. PATCH versions contain only bugfixes e.g. stylesheets won't compile, features are missing by mistake, etc.
- MINOR: These are routine releases. They will contain changes to what's shown on the map, how they appear, new features added and old features removed. They may rarely contain changes to assets i.e. shapefiles and fonts but will not contain changes that require software or database upgrades.
- MAJOR: Any change which requires reloading a database or upgrading software dependecies will trigger a major version change.
The changes are described in the changelog.
This project started as a fork of a default OSM map style OpenStreetMap Carto (OSM Carto) about version 5.3.1. Fractal shares a lot of the ideas and code with it, including CC0 1.0 license, but some of them might need rework in the future:
- Release process will be probably more relaxed
- Usecases were meant as a high level framework for developing the style, however that did not work well enough
Basic documentation about OSM Carto is provided on the OSM wiki page Standard tile layer. It includes such useful links as:
- Map key - this is quite big and still incomplete list of the features found in this style
- OpenStreetMap Carto Tutorials - this is a good place to get more informations about the project
Map scalabillity issues (using the most neutral properties, like typical size and objects hierarchy) are discussed in these two blog entries: