turnrestrictions plugin

The turnrestrictions plugin is currently under development.
You can download the current version from the OSM SVN. It isn't integrated into JOSMs plugin management feature yet. By 04/2010 you'll be able to download and update it via JOSM preferences too.

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Introduction

In OpenStreetMap a turn restriction limits navigation options. They restrict whether one can navigate from one way to another or not. For instance, the turn restriction depicted below forbids to drive straight. Vehicles have to turn left at the junction.

Turn restrictions are important for routing and navigation software which are based on OSM data.

The turnrestrictions plugin supports editing of turn restrictions. It consists of two major components:

1. Turn Restriction Toggle Dialog - the turn restrictions toggle dialog is displayed on the right in the Toggle Dialogs Section. It displays the list of turn restrictions in the current data set and allows to create or delete turn restrictions, or to launch the Turn Restriction Editor to edit a turn restriction.

2. Turn Restriction Editor - the Turn Restriction Editor is a special purpose editor for turn restrictions.

Terminology

Technically, a turn restriction is an OSM relation. A turn restriction

• must have a relation member with role from referring to a way. We call this way the from-way.
• must have a relation member with role to referring to a way. We call this way the to-way.
• must have at least of relation member with role via referring to a node or way. We call these objects via-object.

Use Cases

Creating a turn restriction

There are several possibilities to create a new turn restriction. Firstly, you can lauch the Turn Restriction Editor for a new turn restriction from the Turn Restriction Toggle Dialog:

1. Click on in the Turn Restriction Toggle Dialog. Alternatively, select New from the popup menu.

Alternatively, you can launch a new editor with a keyboard shortcut:

1. Press the shortcut for creating or editing a turn restriction. On most plattforms the shortcut is Ctrl-Shift-T.
2. If objects in the current JOSM selection already participate in a turn restriction, the following window pops up.
   
   Just click on Create new turn restriction to launch the turn restriction editor for a new turn restriction. Alternatively, press the key n or hit Enter.

In both cases, the turnrestrictions plugin initializes the new turn restriction with objects from the current JOSM selection:

1. The first selected way in the JOSM selection becomes the from-way.
2. The last selected way in the JOSM selection becomes the to-way
3. If the from- and the to-way have a node in common, this node becomes a via-object.

A fast way to create a turn restriction is therefore to

1. Select the from- and to-way in JOSM
2. Press Ctrl-Shift-T
3. Choose the type of the turn restriction and save it.

Editing a turn restriction

There are several possible ways to launch a Turn Restriction Editor in order to edit a turn restriction. Firstly, you can lauch the Turn Restriction Editor for an existing turn restriction from the Turn Restriction Toggle Dialog:

1. Select a turn restriction in the Turn Restriction Toggle Dialog
2. Click on . Alternatively, select Edit from the popup menu.

Alternatively, you can launch a new editor with a keyboard shortcut:

1. Press the shortcut for creating or editing a turn restriction. On most plattforms the shortcut is Ctrl-Shift-T.
2. If objects in the current JOSM selection already participate in a turn restriction, the following window pops up.
   
   Just double-click on the turn restriction you want to edit. Alternatively, for the top 9 turn restrictions displayed in the popup window you can use the shortcuts 1 to 9 to launch the Turn Restriction Editor. In the example above, you would press 1 to start editing.

A fast way to edit a turn restriction is therefore to

1. Select the from- or to-way in JOSM
2. Press Ctrl-Shift-T
3. Type 1 to lauch the Turn Restriction Editor

Deleting a turn restriction

There are several possible ways to delete a turn restriction. Firstly, you can delete it in the Turn Restriction Toggle Dialog:

1. Select a turn restriction in the Turn Restriction Toggle Dialog
2. Press DEL or click on . Alternatively, select Delete from the popup menu.

Alternatively, you can launch a Turn Restriction Editor and click on in its toolbar.

<!-- * --> <!-- Turn Restriction Toggle Dialog --> <!-- * -->

Turn Restriction Toggle Dialog

The Turn Restriction Toggle Dialog helps you to keep track of the turn restriction in the current edit layer.

Turn Restriction Editor

Basic Editor

Advanced Editor

Resolving Errors and Warnings