Kaart: Water Features

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Introduction

This document provides information on how to map various features in OSM that interact with water bodies and/or waterways. This includes piers, slipways, ferries, and more. For more information on how to map OSM features that interact with roadways like bridges, culverts, and fords, please refer to the Kaart: Tunnels, Bridges, Fords, Etc.(link) page.

Prerequisites

You should be familiar with mapping in OSM and how to map nodes/ways. You should have an understanding of how to map pedestrian ways and roadways in OSM.

Skill Instruction

Ferries

Ferries are boats or ships used for conveying cargo or passengers across bodies of water from one destination to another. Ferries are typically used for transport over short distances. Examples include crossing a river, traveling to an island, or cutting across a lake.

Since ferries can be a form of public transportation similar tto bus services, these should be connected to road networks when possible. To specify the type of ferry transportation(passengers, bicycles, cars, etc.) use tags that denote access=*.

  • As an example, if a ferry allows both bicycles and pedestrian foot traffic, the following tags would be added: bicycle=yes and foot=yes.

Be sure to consult the wiki for all tags that are appropriate for mapping ferries. Local community standards are an important consideration when mapping features such as this.

Ferry Terminals

When mapping the location of the ferry terminal, add amenity=ferry_terminal to the node/area. Other useful tags include:

When a ferry line is part of a public transportation network that carries passengers and if the ferry routes are mapped as public transport relations, additional tags can be added to the ferry terminal: public_transport=* and ferry=*. For more information see the Kaart: Route Relations(link) page.

Ferry Routes

Ferry routes describe the actual routes that boats/ships travel across. This applies to small boats used to ferry passengers as well as large boats that carry passengers, bicycles, and cars.

How to map ferry routes:

  • Make sure each way connects to a stop (amenity=terminal) on either side of the body of water.
    • Make sure it is connected to a highway=* on either side.
  • Add the tag route=ferry to the way.

How to map ferry route relations: Ferry route relations have multiple routes on them. Only use this method if there is more than one route.

  • Draw each route and connect it on either side of the body of water.
    • Make sure each way connects to a stop (amenity=terminal) along the route and that the next way of the route starts at that point.
    • Make sure it is connected to a highway=* on either side.
  • Create a new relation.
  • Add the following tags to the relation:
  • Add the members in the following order:
    • Stops and platforms first in the order the route goes.
      • Give each one the role of stop or platform respectively.
    • Add the ways in the order the route goes.

Note: To make sure all ferry route relations are routable, add route=ferry to each way of the relation.

Slipways

Slipways, sometimes referred to as boat ramps or bot launches, are ramps that boats use to access waterways or water bodies. These are often concrete, but may be unpaved, dirt ramps.

How to Map

  • Draw in a service road using satellite imagery.
  • Add the tag leisure=slipway to the last node of a service road that leads up to the edge of the body of water.
    • This node should not be connected to the body of water, nor cross the body of water.
  • The physical part of the slipway can be specified further with service=slipway.
  • Additional tags can be used to specify attributes of the slipway:

Piers

Piers are raised structures over water that allow pedestrian traffic. These are commonly made with wood and are supported by pillars made of wood or concrete. Sometimes, these can be floating on the surface of the water instead of elevated above it. There are two common approaches to mapping these features in OSM which are dependent on factors such as size of the pier.

Piers can be mapped as:

  • Linear ways
  • Closed areas

Procedures on how to map piers could vary depending on local community standards, so be aware of which method to use when mapping piers.

Mapping as a Way

For small and/or narrow piers:

  • Draw a linear way in OSM.
  • Add the tag man_made=pier to the entire way.
  • Tags like name=* or floating=* can be added to provide additional information about the pier.

This is the simplest method to map piers in OSM, however, it may be more accurate to map piers as areas in many cases. This is because most piers, including small ones, could be more accurately represented by an area instead of a single linear way.

Mapping as an Area

For wider piers or to represent the area of both small and large piers:

  • Create a closed area as close as possible to the pier's outline per imagery.
  • Add the tag man_made=pier to the entire area.
  • Tags like name=* or floating=* can be added to provide additional information about the pier.

Connectivity

There are a few situations where you may need to connect the pier to other features to either improve routing or show how it relates to the other features.

  • Coastlines:
    • Connect the shore end of the pier to the coastline to show how they relate and if it makes sense to do so.
  • Pier is a linear way:
    • Add highway=* to the pier to enable routing for ferry terminals/routes.
    • Make sure it's connected to the road network and the ferry route.
  • Pier as an area:
    • Draw a new highway=* along the pier to enable routing for ferry terminals/routes.
    • Make sure it's connected to the road network and the ferry route.

insert images here

Docks

Docks are enclosed areas for ships or boats where the height of the water can be managed. In some cases, the water can be drained entirely. They can be located at/around shorelines.

How to Map

Docks can be mapped one of two ways: as an area or as a node.

  • Use available imagery and the data to determine which method works best for your situation.
  • Area: Use satellite imagery to draw a polygon around the area.
  • Node: Place the node in the center of the area.

To define the type of dock, add a more specific tag in combination with waterway=dock.

  • dock=tidal
    • A dock with consistent water level maintained by artifice in an otherwise tidal area, in order to make loading and unloading of ships easier, or to have a safe harbor in areas with a large tidal difference.
  • dock=drydock
    • A dock which can be emptied of water. Useful for inspecting and maintaining otherwise submerged parts of ships.
  • dock=floating
    • Floating docks are usually a large floating structure with the purpose to lift a vessel out of the water for maintenance or inspections of the wet surface of the hull.

Note: In North American English, the terms pier and dock can be used interchangeably. Piers are raised structures above the water that juts out from the shore. Docks are man made structures that are utilized for boats and/or ships.

Example of a dock=tidal
Example of a dock=drydock
Example of a dock=floating

Dams

A dam is a manmade structure that stops or greatly restricts the flow of water in a river or other waterways. This blockage often creates a reservoir on the upstream side of the dam. These structures are used to collect or store water for a variety of purposes, including irrigation, aquaculture, industrial use, hydroelectric power, or human consumption after water treatment. Dams can be any barrier that is used to hold back water. Because of this, dams do not normally have water flowing on top of them.

Dams can be mapped as:

  • Nodes
  • Ways
  • Areas

Refer to OSM guidelines when mapping dams. Local community guidelines should also be considered. It is best practice to add name=* if the name of the dam is known. Refer to the wiki for more useful tags to add. If the body of water upstream of the dam is mapped, this will usually be tagged water=reservoir.

Mapping as a Node

  • Use available imagery to identify the location of the dam.
  • Add a node to the linear waterway feature where the dam is located.
  • Add waterway=dam to the node.

Mapping as a Way

This method is commonly used for small and/or narrow dams.

  • Use available imagery to identify the location of the dam.
  • Use satellite imagery as a guide to draw a line feature where the dam is located.
    • This will typically be adjacent to the reservoir outline, but isn't a requirement.
    • The direction the way is drawn plays an important role. Use the left side is higher, right side is lower convention that is common with other vertical features like natural=cliff and barrier=retaining_wall.

Mapping as an Area

This method is commonly used for large or wide dams.

  • Use available imagery identify the location of the dam.
  • Use satellite imagery as a guide to draw an area feature where the dam is located.
    • It may share ways with the outline of the reservoir, partly overlap the water, or be drawn directly adjacent to the reservoir.
  • Add waterway=dam to the way.

Highways Over a Dam

There is some dispute in the OSM community on how to map interactions between highways and dams. This interaction can be pretty common, since roads can often cross dams. There are a few proposed methods on how to map these interactions, but since the OSM Wiki does not currently have a universally accepted solution, it is important to refer to the community guidelines if you are unsure which solution to use when mapping a roadway that travels over a dam.

  • highway=* and waterway=dam as one feature.
    • Use available imagery to identify the location of the dam/highway.
    • Use satellite imagery as a guide to draw a line feature where the dam/highway is located.
    • Add highway=* and waterway=dam to the way.

Note: QA tools such as validators may return a warning when mapping roadway/dam interactions like this. The wiki suggests this error can be due to an overly generic rule when highway=* and waterway=* is on the same linear way, and it also suggests this is a valid exception.

  • highway=* as way and waterway=dam as an area.
    • Use available imagery identify the location of the dam/highway.
    • Use satellite imagery as a guide to draw a line feature where the highway is located.
    • Use satellite imagery as a guide to draw an area where the dam is located.
  • highway=* and waterway=dam as separate line features.
    • Use available imagery to identify the location of the dam/highway.
    • Use satellite imagery as a guide to draw a line feature where the highway is located.
    • Use satellite imagery as a guide to draw a line feature where the dam is located.

Note: With this mapping solution, these two ways may share some nodes.

For further reading on roadway/dam interactions and thee proposed solutions on how to map them, refer to the following wiki pages:

Practical Application

Suggested Bookmarks

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