Openstreetmap Download Network
Vanesa Domagala
I am looking for a solution to parse OSM PBF files and obtain a road network that is navigable offline. Ideally, it should split ways at intersections with other ways and country boundaries and deduce traversing options based on the oneway and access tags.
Prototype: A Node network consists of marked junctions called Nodes, and Routes interconnecting the Nodes. On the road, every Node is marked with a number, code or name, and it has pointers to adjacent Nodes in different directions. Put differently, two adjacent Nodes always point to each other, which defines the route between these two Nodes. In between the Nodes, the route is waymarked in both directions with arrows or a symbol, often without the Node labels. The symbol is the same for all the routes in a Node network.
The Node network concept can be confusing if you think of routes as e.g. waymarked hiking trails each with its own symbol. You'll have to rethink to make sense of the network routing structure, where you piece Node2Node sections together to make your own unique trip over the network, using the network Nodes as labeled waypoints. Once the Node network is in place, operators can create and offer recreational routes by simply publishingh a list of Nodes representing each route.
For example, in Germany many foot networks use the Yellow Diamond ("Gelbe Raute") as the symbol for a walking network. All routes are waymarked with the same symbol, which doesn't make sense until you understand the node network structure: the symbol leads you to the next Node, and there you choose the next section. Other countries use similar systems.
Node networks are mainly used for recreational purposes. One finds an area of interest, plans a trip within the network or interconnected networks, and writes or prints a list of Nodes to follow. Of course, this process is increasingly digitized with planner sites, planner apps, gpx output, rendering apps and navigation apps.
Many Node networks use numbers as labels. Variants include using letters, codes or names instead of numbers, or different colour markings on the Node2Node routes. Arrows and pointers may be replaced with strategically placed signposts, so the user has to look around to find the path leading to the next node on the list. This makes no difference when planning a trip over the Node network. Planned trips in the end consist of a chain of numbers, codes or names to follow. Sometimes additional details such as a colour code are needed.
A particular variant uses coloured routes to interconnect the network Nodes. Often, the coloured routes existed first, and later, where the colour routes started, crossed or touched, labeled Nodes were created. On the road, you cannot choose the next number, you choose which colour to follow. The trip planner app has to add this colour information to the user output. (2021-07-06 One of the two Dutch operators who do it this way has confirmed that they will add the codes to the symbol shields on the Node posts later this year. 2021-11-11 Update: The numbering operation has actually started. 2023-10 Update: the Wandelnet Planner now supports coloured routes, by showing the Node2Node route colours in the user output).
A less useful variant is a Node network by design, but on the road the destination nodes are not indicated at the network Nodes. To make a choice, the user needs external information, e.g. a map showing paths and nodes, or a gpx, or a Node strip indicating the direction. Typically, after some time the operator is made aware of the user problem, and adds a solution to indicate the different directions at the nodes. E.g. the operator adds transparent stickers with the destination numbers.
In Germany, France, Switzerland and Austria, many walking Node networks exist using Node names as labels, instead of Node numbers or codes. Because most networks use numbers or codes consisting of a letter and a number as Node labels, these networks were only recently (2020) recognized as functional Node networks. The tagging scheme, maintenance tools and planners have been adapted (2021Q3) to accommodate named Nodes.
Different transport modes are supported. New transport modes can be added as they appear on the road. The transport modes are indicated by tags in the route relations, in the network relations and on the network Nodes. A letter is used to indicate the transport mode: w Walking, c Cycling, h Horse, i Inline skating, m Motorboat, p Paddling (e.g. canoe). This is the same as for regular (non-node_network) routes.
A specific transport mode may require special or additional tagging. For example, bicycle node networks require intricate handling of route differences according to the direction of travel. The existing route tagging system, using forward and backward roles to record both directions of travel in one route relation, is therefore accommodated in the Node network system, independent of transport mode.
The Node network tagging system supports the same geographical scopes as regular recreational routes: l for local, r for regional, n for national and i for international. Currently, two scopes, l and r, are in use for Node networks. The Dutch and the Belgians use r for all node networks, because the extent of the networks tended to be regional. The Germans and the French however, tend to use regional scope for cycling networks, but local scope for walking networks, because for cycling the Nodes and routes tend to be regional, while for walking the Nodes and the Node2Node routes are generally local.National and international Node network routes are not currently known, but if they arise, they can be accommodated within the same framework. Other scopes, e.g. intercontinental or (why not) interplanetary, would require a new scope indicator, say g for global, s for solar system, and tools and applications would need to adapt to handle these scopes.
Interconnecting networks with different scopes is still a challenge, which will be addressed in the near future. 2021Q3: One example has popped up in Ghent (B). A local cycling Node network has been created within an area where a regional cycling network already has Nodes. It looks like this development will also happen in other places and also for walking.
Waymarking on the road or waterways may differ between regions, and may require some getting used to when following the routes on the road or water. Many cycle networks use separate posts and shields for the Node2Node route waymarking, where walking networks often use simple stickers and small shields on landposts, street furniture and trees, or combined with regular route symbols on multipurpose shield posts. Some give the next Node label on every shield, some just use an arrow or shield without a label. In Germany and France, many operators have integrated all waymarking and direction-pointing systems for a particular transport mode into one system of named signposts and shields for all purposes. In Nederland, boat networks and canoe networks use each others Nodes (same numbers), but distinguish the vessel types by a colour code.
Different topological styles may be found as well. Some operators use end Nodes (1 route) or middle Nodes (2 routes) at POI's, some don't. Some operators have non-numbered route splittings, where you would expect a netwok Node but there simply isn't one. Some operators use intermediate network Nodes when there are alternative ways to connect two network Nodes; some simply allow two routes between a set of Nodes. Some have loops on a single Node. Some use a single number when choice points are close together; others tend to assign different Node numbers even when the Nodes are only 15 m apart.
Node networks are maintained on the road by various (and often changing) operators. Most operators have their own network maps and sometimes a planner site or app. OSM uses the Nodes and Routes as found on the road and in the field. In The Netherlands, mappers are allowed to use the Wandelnet Node route planner as a source for the very detailed walking Node network covering almost the whole country.
Node networks started out as separate cycling Node networks in Belgium, soon copied by The Netherlands. Later different networks interconnected and the system was also applied to walking. Nowadays, for cycling in Nederland, the whole country is one big Node network; the walking network is almost covering the country, and Node networks for horse riding, motorboat, canoe and inline skating are being rolled out. Other countries are seen to follow this development.
The basics of OSM-tagging of Node networks came from a discussion on talk-nl in September 2008, and it was fleshed out in the months after that. Since then, many things have changed but the basic modeling system is the same. This development is still going on: e.g. the tags for canoe and motorboat Node networks were added in 2018, support for colour routes was added in 2019, and support for named Nodes was added in 2021.
This page gives the reasoning and the essentials for all Node networks. It explains how we arrived at the current data model. Details for a particular type of Node network can be found on various tagging pages. Variations and rules for particular countries should be described on localized pages.
The objective was and still is, to make the Node networks routable and planner-ready, and renderable as special networks, different than regular cycling, hiking, horse, canoe, motorboot and inline skate routes. So we are building a model for data use, while staying as close to the real world as possible. This can be compared to the way roads are mapped and connected as linear features to enable routing, while in reality they are areas.
Knooppuntnet Analysis has been designed to perform integrity checking and quality checking on Node networks and Node network elements. The results are presented by network as "facts" with direct edit links to OSM/Id and JOSM.
Although in theory Node networks could be defined at local, regional, national and international scope, currently nearly all node networks in The Netherlands and Belgium are still defined as regional (network=rXn), with the exception of one lwn network used for development and testing. Cycling is still the dominant application of Node networks. Therefore, in this tagging instruction we will assume regional scope, and use c for cycling to explain the tagging. For other transport types, use w for walking, h for horse, p for paddling (canoe), i for inline skating instead of c for cycling, in these tags:
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