User:Mashin/Rapids unification

Rapids
Proposal status:	Draft (under way)
Proposed by:	Mashin
Tagging:	water=rapids Data item
Applies to:	, , ,
Definition:	A unifying system for rapids and whitewater features mapping.
Statistics:
Draft started:	2021-11-27
RFC start:	n/a
Vote start:	n/a
Vote end:	n/a

Background

Rapids are sections of rivers where riverbed has a relatively steep gradient and water flows through with increased velocity and turbidity. Knowing details about rapids ahead is essential for safe practicing of water sports.
Currently, several mapping approaches exist that cause conflicting situations with other water features or duplication of objects. This proposal aims at providing an amendment to the tagging suggestions in order to achieve:

1. Simple and intuitive guideline
2. Provide solution with minimal impact on current tagging and with little requirements for modification of already existing features.
3. Maintain consistency and spirit of established water features tagging.
4. Remove practice of creating duplicated features.

Proposed solution

Linear (Point) features

Primary way of tagging rapids is proposed to draw as a line feature along the median of a river section and tagged as waterway=rapids.
Alternatively: by placing a new node on waterway=river line and adding tag waterway=rapids.
Explanation:

• This is consistent with tagging of routable water features and obstacles as waterway=*
• Rapids waterway=rapids line should not duplicate or overlap with waterway=river line, but rather be inserted between two waterway=river lines.
• Rapids line should be inserted into Relation:waterway to preserve river connectivity.
• Additional optional tags can be applied to rapids line or point:
  • point: whitewater:rapid_name=*, whitewater:rapid_grade=*
  • line: whitewater:section_name=*, whitewater:section_grade=*
  • Note: Previously there has been an attempt to have single set of tags for both points and lines whitewater:name=*, whitewater:grade=*. See 1, 2

Area features

Full area of water rapids are to be mapped as closed way tagged with natural=water + water=rapids.
Explanation:

• This is consistent with currently popular tagging of water areas as natural=water + water=*
• Rapids water=rapids area should not duplicate or overlap with water=river area. This is similar to the rationale that water=reservoir areas do not overlap with water=river area of river that flows through the reservoir.
• No additional tags such as name are necessary as those are part of linear (point) features.

Effect on existing features

1. waterway=rapids nodes: Remain valid features.
2. waterway=rapids lines: Remain valid features. If overlapping with waterway=river line, the duplicate waterway=river section should be removed.
3. waterway=rapids areas: To be retagged as natural=water + water=rapids. Other tags preset on area should be moved to line feature. Overlapping part of water=river should be removed.
4. whitewater:*=* nodes & lines: Add waterway=rapids tag.

Features/Pages affected

Tag:water=rapids, Tag:waterway=rapids, Whitewater sports, Proposed features/Key:whitewater:grade, WikiProject Whitewater Maps/Proposals

External discussions

Please comment on the discussion page.