Editing Tide gauge (section)

==History==
Sea-level measurements were made using simple measuring poles or "tide staffs" until around 1830, when self-recording gauges with mechanical [[Float (nautical)|floats]] and stilling wells were introduced.<ref>[http://noc.ac.uk/science-technology/climate-sea-level/sea-level/tides/tide-gauges/tide-gauge-instrumentation Tide gauge history UK National Oceanographic Centre] {{Webarchive|url=https://web.archive.org/web/20150824020453/http://noc.ac.uk/science-technology/climate-sea-level/sea-level/tides/tide-gauges/tide-gauge-instrumentation |date=2015-08-24 }}</ref>

Tidal poles and float gauges were the primary means of sea-level measurement for over 150 years and continue to operate at some locations today. While still part of modern-day tide gauge instrumentation, these technologies have since been superseded by pressure gauges (similar to [[depth gauge]]s), acoustic/ultrasonic gauges, and radar gauges.{{citation needed|date=May 2018}}

The following types of tide gauges have been used historically:<ref>{{cite web|title=History of tide gauges|url=http://tide.gsi.go.jp/ENGLISH/history.html|work=Tide Observation|publisher=[[Geospatial Information Authority of Japan]]|access-date=2014-04-19|archive-date=2013-01-05|archive-url=https://web.archive.org/web/20130105092332/http://tide.gsi.go.jp/ENGLISH/history.html|url-status=dead}}</ref>

* Kelvin type tide gauge
* Fuess type tide gauge
* GSI type tide gauge
* High accuracy automatic tide gauge
* High resolution automatic tide gauge