The process of rendering a map generally means taking raw geospatial data and making a visual map from it. Often the word applies more specifically to the production of a raster image, or a set of raster tiles, but it can refer to the production of map outputs in vector-based formats. "3D rendering" is also possible taking map data as an input. The ability to render maps in new and interesting styles, or highlighting features of special interest, is one of the most exciting aspects having open access to geodata. Developers in and around the OpenStreetMap community have created a wide variety of software for rendering OpenStreetMap data. The data can also be converted to other data formats for use with existing rendering software.
Rendering on OpenStreetMap servers
The most obvious examples of rendering OpenStreetMap data, are those found on the openstreetmap.org homepage. Click the drop-down in the top right to switch between layers showing different rendering styles. There are several layers created using Mapnik software including the default 'Standard' layer. To understand more about the infrastructure involved in rendering and serving these tiles map styles, see Component overview.
There are limitless dimensions of flexibility involved in rendering. Most rendering software supports some kind of stylesheet for controlling things like colour, line widths, text orientation, icons for points of interest, and many very subtle visual factors.
The main options for conventional 2D raster rendering:
- Mapnik - Requires PostgreSQL and various C++ libraries. It is designed to be fast and is suitable for tile generation on high-end servers but it isn't particularly easy to set up.
- TileMill is a frontend solution to handle a user defined rendering of Mapnik. Uses simpler style format.
- Osmarender - XSLTs which does OSM XML to SVG transformation. tiles@home was a project which uses Osmarender to create a tile set for serving a map layer alongside Mapnik's, but Osmarender can also be a good option for doing one-off renderings. SVG format allows you to do post-processing tidy up tweaks (see other options below). It was withdrawn from the main map at osm.org on 1th March 2012.
Other renderers, including vector rendering:
- Custom python script for mapnik.
- Maperitive is local file (.osm, .osm.bz2 and GPX) desktop rendering application, with rendering rules defined in a text file. Generates BMP, PNG and SVG output. Not designed for high performance rendering or huge volumes of data, but easy to set up and flexible, and a good option for one-off rendering (e.g. a map of your city). It also has a tile generator, hillshading, elevation colouring and lots of other features. Runs on Windows, Linux, Mac. Written in C#
- osmrender.pl - simple maps easily drawn with a Perl program. Uses *.osm as input.
- Mapweaver - Successor of mapgen.pl Perl rendering, OSM to SVG and with Inkscape to PNG or PDF, automatic map key. Supports street and POI lists, grids and coordinate overlays. Automatic extraction of desired place out of OSM file. Not running under Windows.
- CartoType - is a multi-OS rendering and routing library under licence. Runs on Windows, iOS, Android, Mac OS, Unix. Written in C++.
- Halcyon - is an AS3 (ActionScript) rendering library developed by Richard Fairhurst and used within Potlatch2
- Kosmos is local file (.osm) rendering engine based on GDI/.NET (Windows), with rendering rules defined on a wiki page. Not designed for high performance rendering or huge volumes of data, but very flexible, and good option for one-off rendering. Superseded by Maperitive
- Mapsforge - free and open toolbox that enables the community to easily create new OpenStreetMap-based applications. Provided tools and APIs include solutions for map rendering, route planning and navigation, POI indexing and search, map overlays and more. Written in java, target platform seems to be Android devices.
- Pyrender - a collection of ideas, and some code in Python for various rendering server steps
- Kogutowicz - An extensible, multi-purpose Java based rendering engine. The project is under development. Currently not usable by end users.
- Cobra - abandoned .Net/mono rendering engine with SVG and raster output.
- Ceyx - .osm parser and MapCSS renderer under active development. MapCSS is the stylesheet language used by Halcyon to describe the look of a map and if you ever worked with HTML, you will quickly feel at home there. Ceyx needs python, python-cairo and pygtk (for pango/pangocairo).
- Maposmatic - can render maps with a grid and street index. Written in Python/Django + mapnik :)
- osmbrowser - can load large areas of OSM data and render them in vector graphics.
- MapDiff generates Animation, written in D
- Memphis (Renderer)  is a map-rendering application and a library for OpenStreetMap written in C using eXpat, Cairo and GLib. It's licensed under the terms of the GNU Lesser General Public License.
- Hardware_accelerated_real-time_rendering - using graphics card to render images in real-time, instead of displaying prerendered tiles
- Libosmscout offers simple, high-level interfaces to offline rendering and routing functionalities based on OpenStreetMap data.
- Kothic a MapCSS/0.2 python rendering engine.
- Smrender a rules-based rendering engine written in C
- Kartograph a python framework to create SVG maps
- OpenStreetMap 3D - OSM in 3D as a web service
- OSM2World - Java tool that creates 3D models from OSM data files
- ShugenDoMap - Multi-platform OSM realtime 3D renderer. Especially designed for mobile platforms like smart phones and tablets.
- Osm2pov - Tool for creating isometric maps from OSM data
- Kendzi3d - Plugin for JOSM, allows viewing of edited data in 3D
- Renderers feature list - a look a capabilities of different renderers
- Creating your own tiles - Various options with quick descriptions
- List of OSM based Services - mainly a list of different map renderings
- Category:Renderers - wiki category for pages about renderers
- 3D Development
- OpenWhateverMap, a map with a patchwork of different rendering styles, suitable for demo and fun!