Kaart: Waterways/sandbox

[[Features|]]: Kaart: Waterways/sandbox

Description

Areas of water including rivers, canals, streams, lake and reservoirs

Tags

waterway=river waterway=stream waterway=tidal_channel waterway=canal waterway=ditch waterway=drain waterway=pressurised natural=water water=*

Introduction

Waterways are the linear water features including rivers, canals and streams, which flow towards larger water areas such as oceans, lakes, reservoirs or other larger rivers. All these water features listed previously may eventually interact with the normal road network, requiring for these to be crossed somehow by use of bridges, tunnels, ferries, fords, or others, making it always important to add these features into OSM as accurately as possible, as these intersections may be an obstacle hard to cross when not well described.

Prerequisites

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

Skill Instruction

Rivers

The visible main waterways (as seen on the satellite imagery) on OSM are known as waterway=river. Always remember that inland water flows based on gravity and pressure differences. through As gravity plays a key role causing the flow to be from the higher to the lower elevation.the least resistance and gravity plays an important factor in the flow, which will naturally connect with larger water bodies (oceans, lakes or with other larger rivers). Rivers can be very long and hard to follow with the available satellite imagery as the image resolution or even shrubbery may interfere with its visibility, and while ideally these should be drawn from start to finish, try at least drawing in as much of it as needed to depict properly its interaction with the road network. Most rivers are usually crossed over by use of a bridge=yes + layer=1, while a few others scattered around the world are crossed going under its riverbed through a tunnel=yes + layer=-1. A third fairly common option to cross a river is over it's surface from one end of one shoreline with amenity=ferry_terminal to another similar found on the opposite side, connecting both terminals by drawing-in the approximate water route which is then tagged as route=ferry.

Major rivers are commonly fed by other rivers or streams along its total length, having each one its own name and other descriptive features.

Streams

A waterway=stream is a much smaller kind of waterway that may even be jumped over, usually averaging +/- 3 meters wide.

Tidal Channels

A waterway=tidal_channel are waterways found within the marine coastal areas which carry water dependent on the lunar tides during certain times of the day, causing depth variances throughout each day.

Canals

These waterway=canal are man-made water distribution methods used commonly for irrigation or other human-controled water needs.

Ditches

These are noticeably even more narrow man-made waterways. Usually are not lined with any artificial materials and are made mostly as straight segments.

Drains

These are also man-made waterways, typically lined with concrete or other artificial materials. These are used to carry unwanted water from a location.

Pressurised

A waterway=pressurised is an artificial waterway through which water (or other liquids) flow in a closed space without air. These are seen as conduits in the form of pipelines, . More data on how to map and tag these, including the details describing its usage or other relevant data may be found specified on OSM as man_made=pipeline

How to Map

• As with any other type of "way", a waterway's flow direction is determined by how it's been drawn into OSM and special care should be taken to enter these correctly when adding them to the map.

• Try to draw in as much of the visible waterway (or whatever is convenient to better depict its interaction with the roads) while using satellite imagery. For larger areas covered with water by the rivers try using natural=water + water=river. You may find more detailed information here.
  • If a waterway=* already exists drawn in on the map, verify it's features, type and how it interacts when it meets with a road (over, through, under).
  • There should never be any node connecting a highway with the body of water, unless it is being crossed over with a ford=yes (or when being crossed on a ferry).

• You may add other additional tags to specify its even more attributes and describe the waterway further, such as:
  • name=*
  • description=*
  • width=* – To indicate the width in meters.
  • intermittent=yes – Indicates that waterway or water body is intermittent

Mapping as an Area

As rivers do vary its width along its course, it becomes necessary to draw-in accordingly. On the narrower segments of a river just drawing in a line to represent it is more than enough. The complete river's course should be drawn in as a linear feature waterway=river and multipolygons should be added on the wider segments following the riverbank shorelines with use of the natural=water + water=river tags to depict these areas.

In those cases in which islands are present inside these riverbanks, these should also be mapped accordingly. The more complex cases with islands multipolygon relations should be used. More detailed information on how to map may be found here.

Practical Application

Supportive Material:

• Sandboxes
• Presentations
• Videos

Suggested Bookmarks

• Kaart: Waterway_features(link)
• Waterways
• Relation:waterway
• natural=water + water=river – For water body areas
• waterway=stream – A naturally-forming waterway that is too narrow to be classed as a river
• waterway=tidal_channel – A natural intertidal waterway in mangroves, salt marshes and tidal flats with water flow in the direction of the tide
• waterway=rapids - a rapid
• natural=water + water=river + intermittent=yes – Used to indicate a water body does not permanently contain water
• natural=shingle – An accumulation of rounded rock fragments on a beach or riverbed
• natural=sand – An area covered by sand with no or very little vegetation
• man_made=dyke and man_made=embankment – Built to restrict the flow of water
• WaterwayMap.org – Website which shows if the waterways are topologically connected
• Community Forum - OSM Community forum support on "How to Draw a Waterway"