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projection</a></li> <li><a href="/wiki/Reference_ellipsoid" class="mw-redirect" title="Reference ellipsoid">Reference ellipsoid</a></li> <li><a href="/wiki/Satellite_geodesy" title="Satellite geodesy">Satellite geodesy</a></li> <li><a href="/wiki/Spatial_reference_system" title="Spatial reference system">Spatial reference system</a></li> <li><a href="/wiki/Spatial_relation" title="Spatial relation">Spatial relations</a></li> <li><a href="/wiki/Vertical_position" title="Vertical position">Vertical positions</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="color: var(--color-base)">Technologies</div><div class="sidebar-list-content mw-collapsible-content hlist"> <ul><li><a href="/wiki/Satellite_navigation" title="Satellite navigation">Global Nav. Sat. Systems (GNSSs)</a></li> <li><a href="/wiki/Global_Positioning_System" title="Global Positioning System">Global Pos. System (GPS)</a></li> <li><a href="/wiki/GLONASS" title="GLONASS">GLONASS <span style="font-size:85%;">(Russia)</span></a></li> <li><a href="/wiki/BeiDou" title="BeiDou">BeiDou (BDS) <span style="font-size:85%;">(China)</span></a></li> <li><a href="/wiki/Galileo_(satellite_navigation)" title="Galileo (satellite navigation)">Galileo <span style="font-size:85%;">(Europe)</span></a></li> <li><a href="/wiki/Indian_Regional_Navigation_Satellite_System" title="Indian Regional Navigation Satellite System">NAVIC <span style="font-size:85%;">(India)</span></a></li> <li><a href="/wiki/Quasi-Zenith_Satellite_System" title="Quasi-Zenith Satellite System">Quasi-Zenith Sat. Sys. (QZSS) <span style="font-size:85%;">(Japan)</span></a></li> <li><a href="/wiki/Discrete_Global_Grid" class="mw-redirect" title="Discrete Global Grid">Discrete Global Grid and Geocoding</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed plainlist"><div class="sidebar-list-title" style="color: var(--color-base)">Standards (history)</div><div class="sidebar-list-content mw-collapsible-content hlist"><table class="nowrap" style="width:100%;border-collapse:collapse;border-spacing:0px 0px;border:none;line-height:1.2em;"><tbody><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/Sea_Level_Datum_of_1929" class="mw-redirect" title="Sea Level Datum of 1929">NGVD 29</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Sea Level Datum 1929</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/OSGB36" class="mw-redirect" title="OSGB36">OSGB36</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Ordnance Survey Great Britain 1936</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/SK-42_reference_system" title="SK-42 reference system">SK-42</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Systema Koordinat 1942 goda</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/ED50" title="ED50">ED50</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> European Datum 1950</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/South_American_Datum#SAD69" title="South American Datum">SAD69</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> South American Datum 1969</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/GRS_80" class="mw-redirect" title="GRS 80">GRS 80</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Geodetic Reference System 1980</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/ISO_6709" title="ISO 6709">ISO 6709</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Geographic point coord. 1983</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/North_American_Datum#North_American_Datum_of_1983" title="North American Datum">NAD 83</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> North American Datum 1983</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/World_Geodetic_System" title="World Geodetic System">WGS 84</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> World Geodetic System 1984</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a class="mw-selflink selflink">NAVD 88</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> N. American Vertical Datum 1988</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/European_Terrestrial_Reference_System_1989" title="European Terrestrial Reference System 1989">ETRS89</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> European Terrestrial Ref. Sys. 1989</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/Restrictions_on_geographic_data_in_China" title="Restrictions on geographic data in China">GCJ-02</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Chinese obfuscated datum 2002</td></tr><tr style="vertical-align:top"><td style="text-align:left;padding-left:0.5em;"> <a href="/wiki/Geo_URI_scheme" title="Geo URI scheme">Geo URI</a></td><td style="text-align:right;font-size:90%;padding-right:0.55em;"> Internet link to a point 2010</td></tr></tbody></table> <ul><li><a href="/wiki/International_Terrestrial_Reference_System" class="mw-redirect" title="International Terrestrial Reference System">International Terrestrial Reference System</a></li> <li><a href="/wiki/SRID" class="mw-redirect" title="SRID">Spatial Reference System Identifier (SRID)</a></li> <li><a href="/wiki/Universal_Transverse_Mercator_coordinate_system" title="Universal Transverse Mercator coordinate system">Universal Transverse Mercator (UTM)</a></li></ul></div></div></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Geodesy" title="Template:Geodesy"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Geodesy" title="Template talk:Geodesy"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Geodesy" title="Special:EditPage/Template:Geodesy"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p>The <b>North American Vertical Datum of 1988</b> (<b>NAVD 88</b>) is the <a href="/wiki/Vertical_datum" title="Vertical datum">vertical datum</a> for <a href="/wiki/Orthometric_height" title="Orthometric height">orthometric heights</a> established for vertical control <a href="/wiki/Surveying" title="Surveying">surveying</a> in the <a href="/wiki/United_States" title="United States">United States of America</a> based upon the General Adjustment of the North American Datum of 1988.<sup id="cite_ref-NA88_1-0" class="reference"><a href="#cite_note-NA88-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>It superseded the <a href="/wiki/National_Geodetic_Vertical_Datum_of_1929" title="National Geodetic Vertical Datum of 1929">National Geodetic Vertical Datum of 1929</a> (NGVD 29),<sup id="cite_ref-NG29_2-0" class="reference"><a href="#cite_note-NG29-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> previously known as the Sea Level Datum of 1929. </p><p>NAVD 88, along with North American Datum of 1983 (NAD 83), is set to be replaced in 2025 with a <a href="/wiki/Datum_of_2022" class="mw-redirect" title="Datum of 2022">new geometric reference</a> frame and geopotential datum, based on <a href="/wiki/GPS" class="mw-redirect" title="GPS">GPS</a> and gravimetric geoid models.<sup id="cite_ref-NEW22_3-0" class="reference"><a href="#cite_note-NEW22-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Methodology">Methodology</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=North_American_Vertical_Datum_of_1988&action=edit&section=1" title="Edit section: Methodology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/w/index.php?title=File:Forecasting_and_Modeling_Storm_Surge.pdf&page=3" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3b/Forecasting_and_Modeling_Storm_Surge.pdf/page3-220px-Forecasting_and_Modeling_Storm_Surge.pdf.jpg" decoding="async" width="220" height="170" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3b/Forecasting_and_Modeling_Storm_Surge.pdf/page3-330px-Forecasting_and_Modeling_Storm_Surge.pdf.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3b/Forecasting_and_Modeling_Storm_Surge.pdf/page3-440px-Forecasting_and_Modeling_Storm_Surge.pdf.jpg 2x" data-file-width="1650" data-file-height="1275" /></a><figcaption>Illustration of vertical datums in the United States.</figcaption></figure> <p>NAVD 88 was established in 1991 by the minimum-constraint <a href="/wiki/Adjustment_of_observations" class="mw-redirect" title="Adjustment of observations">adjustment</a> of <a href="/wiki/Geodesy" title="Geodesy">geodetic</a> <a href="/wiki/Leveling" class="mw-redirect" title="Leveling">leveling</a> observations in <a href="/wiki/Canada" title="Canada">Canada</a>, the <a href="/wiki/United_States" title="United States">United States</a>, and <a href="/wiki/Mexico" title="Mexico">Mexico</a>. It held fixed the height of the primary <a href="/wiki/Tide_gauge" title="Tide gauge">tide gauge</a> <a href="/wiki/Benchmark_(surveying)" title="Benchmark (surveying)">benchmark</a>, referenced to the <i>International Great Lakes Datum of 1985</i> local <a href="/wiki/Mean_sea_level" class="mw-redirect" title="Mean sea level">mean sea level</a> (MSL) height value, at <a href="/wiki/Rimouski" title="Rimouski">Rimouski</a>, <a href="/wiki/Quebec" title="Quebec">Quebec</a>, <a href="/wiki/Canada" title="Canada">Canada</a>. Additional tidal bench mark elevations were not used due to the demonstrated variations in <a href="/wiki/Sea_surface_topography" class="mw-redirect" title="Sea surface topography">sea surface topography</a>, i.e., that MSL is not the same <a href="/wiki/Equipotential" title="Equipotential">equipotential</a> surface at all tidal bench marks.<sup id="cite_ref-NA88_1-1" class="reference"><a href="#cite_note-NA88-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>North American Vertical Datum of 1988 (NAVD 88) consists of a leveling network on the North American Continent, ranging from Alaska, through Canada, across the United States, affixed to a single origin point on the continent.<sup id="cite_ref-NA88_1-2" class="reference"><a href="#cite_note-NA88-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>In 1993 NAVD 88 was affirmed as the official vertical datum in the <a href="/wiki/National_Spatial_Reference_System" title="National Spatial Reference System">National Spatial Reference System</a> (NSRS) for the Conterminous United States and Alaska.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> (see Federal Register Notice (FRN)). Although many papers on NAVD 88 exist, no single document serves as the official defining document for that datum.<sup id="cite_ref-NA88_1-3" class="reference"><a href="#cite_note-NA88-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>The definition of NAVD 88 uses the <a href="/wiki/Friedrich_Robert_Helmert" title="Friedrich Robert Helmert">Helmert</a> orthometric height, which calculates the location of the <a href="/wiki/Geoid" title="Geoid">geoid</a> (which approximates MSL) from modeled local gravity.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2019)">citation needed</span></a></i>]</sup> The NAVD 88 model is based on then-available measurements, and remains fixed despite later improved geoid models.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2019)">citation needed</span></a></i>]</sup> </p><p>Since NGVD 29 used a simple model of gravity based on latitude to calculate the geoid and did not take into account other variations,<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2019)">citation needed</span></a></i>]</sup> elevation difference between points in a local area in it and NAVD 88 will show negligible change from one datum to the other, even though the elevation of both does change between datums.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2019)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Datum_of_2022">Datum of 2022</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=North_American_Vertical_Datum_of_1988&action=edit&section=2" title="Edit section: Datum of 2022"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End,_South_Park,_Seattle_01.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/80/North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg/220px-North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/80/North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg/330px-North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/80/North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg/440px-North_American_Vertical_Datum_at_7th_Ave_S_Shoreline_Street_End%2C_South_Park%2C_Seattle_01.jpg 2x" data-file-width="6000" data-file-height="4000" /></a><figcaption>An unusual vertical datum marker at a <a href="/wiki/Shoreline_street_ends_in_Seattle" title="Shoreline street ends in Seattle">shoreline street end</a> in <a href="/wiki/Seattle" title="Seattle">Seattle</a>.</figcaption></figure> <p>Based on the more recent surveying techniques and data, it was determined that NAVD 88 is both biased (by about 0.5 meters (1 ft 8 in)) and tilted (about 1 meter (3 ft 3 in) coast to coast).<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> To improve the <a href="/wiki/National_Spatial_Reference_System" title="National Spatial Reference System">National Spatial Reference System</a> (NSRS), the National Geodetic Service will replace the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88) with a new geometric reference frame and geopotential datum in 2025.<sup id="cite_ref-NEW22_3-1" class="reference"><a href="#cite_note-NEW22-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>The new reference frames will rely primarily on Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), as well as on a gravimetric geoid model resulting from NOAA's Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project. These new reference frames are intended to be easier to access, and maintain, than NAD 83 and NAVD 88, which rely on physical survey marks that deteriorate over time.<sup id="cite_ref-NEW22_3-2" class="reference"><a href="#cite_note-NEW22-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=North_American_Vertical_Datum_of_1988&action=edit&section=3" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Altitude" title="Altitude">Altitude</a></li> <li><a href="/wiki/Geodesy" title="Geodesy">Geodesy</a></li> <li><a href="/wiki/Sea_Level_Datum_of_1929" class="mw-redirect" title="Sea Level Datum of 1929">Sea Level Datum of 1929</a></li> <li><a href="/wiki/Topographic_elevation" class="mw-redirect" title="Topographic elevation">Topographic elevation</a></li> <li><a href="/wiki/Topography" title="Topography">Topography</a></li> <li><a href="/wiki/Reference_ellipsoid" class="mw-redirect" title="Reference ellipsoid">Reference ellipsoid</a></li> <li><a href="/wiki/Geoid" title="Geoid">Geoid</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=North_American_Vertical_Datum_of_1988&action=edit&section=4" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-NA88-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-NA88_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-NA88_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-NA88_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-NA88_1-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFUS_Department_of_Commerce" class="citation web cs1">US Department of Commerce, National Oceanic and Atmospheric Administration. <a rel="nofollow" class="external text" href="https://www.ngs.noaa.gov/datums/vertical/north-american-vertical-datum-1988.shtml">"North American Vertical Datum of 1988 (NAVD 88) - Vertical Datum - Datums - National Geodetic Survey"</a>. <i>www.ngs.noaa.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2022-02-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.ngs.noaa.gov&rft.atitle=North+American+Vertical+Datum+of+1988+%28NAVD+88%29+-+Vertical+Datum+-+Datums+-+National+Geodetic+Survey&rft.aulast=US+Department+of+Commerce&rft.aufirst=National+Oceanic+and+Atmospheric+Administration&rft_id=https%3A%2F%2Fwww.ngs.noaa.gov%2Fdatums%2Fvertical%2Fnorth-american-vertical-datum-1988.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></span> </li> <li id="cite_note-NG29-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-NG29_2-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUS_Department_of_Commerce" class="citation web cs1">US Department of Commerce, National Oceanic and Atmospheric Administration. <a rel="nofollow" class="external text" href="https://www.ngs.noaa.gov/datums/vertical/national-geodetic-vertical-datum-1929.shtml">"National Geodetic Vertical Datum of 1929 (NGVD 29) - Vertical Datum - Datums - National Geodetic Survey"</a>. <i>www.ngs.noaa.gov</i><span class="reference-accessdate">. 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Retrieved <span class="nowrap">2022-02-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.ngs.noaa.gov&rft.atitle=New+Datums+-+National+Geodetic+Survey&rft.aulast=US+Department+of+Commerce&rft.aufirst=National+Oceanic+and+Atmospheric+Administration&rft_id=https%3A%2F%2Fwww.ngs.noaa.gov%2Fdatums%2Fnewdatums%2Findex.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc93-14922.pdf">"Affirmation of Vertical Datum for Surveying and Mapping Activities"</a> <span class="cs1-format">(PDF)</span>, <i><a href="/wiki/Federal_Register" title="Federal Register">Federal Register</a></i>, vol. 58, no. 120, June 28, 1993 – via NGS</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Federal+Register&rft.atitle=Affirmation+of+Vertical+Datum+for+Surveying+and+Mapping+Activities&rft.volume=58&rft.issue=120&rft.date=1993-06-28&rft_id=http%3A%2F%2Fwww.ngs.noaa.gov%2FPUBS_LIB%2FFedRegister%2FFRdoc93-14922.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUS_Department_of_CommerceUS_Department_of_Commerce" class="citation web cs1">US Department of Commerce, NOAA; US Department of Commerce, NOAA. <a rel="nofollow" class="external text" href="https://geodesy.noaa.gov/datums/newdatums/background.shtml">"Background: Why is NGS replacing NAD 83 and NAVD 88?"</a>. <i>geodesy.noaa.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-07-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=geodesy.noaa.gov&rft.atitle=Background%3A+Why+is+NGS+replacing+NAD+83+and+NAVD+88%3F&rft.aulast=US+Department+of+Commerce&rft.aufirst=NOAA&rft.au=US+Department+of+Commerce%2C+NOAA&rft_id=https%3A%2F%2Fgeodesy.noaa.gov%2Fdatums%2Fnewdatums%2Fbackground.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUS_Department_of_Commerce" class="citation web cs1">US Department of Commerce, National Oceanic and Atmospheric Administration. <a rel="nofollow" class="external text" href="https://geodesy.noaa.gov/datums/newdatums/TrackOurProgress.shtml">"Track Our Progress - New Datums - National Geodetic Survey"</a>. <i>geodesy.noaa.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-07-10</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=geodesy.noaa.gov&rft.atitle=Track+Our+Progress+-+New+Datums+-+National+Geodetic+Survey&rft.aulast=US+Department+of+Commerce&rft.aufirst=National+Oceanic+and+Atmospheric+Administration&rft_id=https%3A%2F%2Fgeodesy.noaa.gov%2Fdatums%2Fnewdatums%2FTrackOurProgress.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=North_American_Vertical_Datum_of_1988&action=edit&section=5" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://tidesandcurrents.noaa.gov/datum_options.html">Tidal Datums</a>, produced for <a href="/wiki/NOAA" class="mw-redirect" title="NOAA">NOAA</a> by its <a href="/wiki/National_Geodetic_Survey" class="mw-redirect" title="National Geodetic Survey">National Geodetic Survey</a></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.usgs.gov/">"United States Geological Survey home page"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=United+States+Geological+Survey+home+page&rft_id=http%3A%2F%2Fwww.usgs.gov%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ngs.noaa.gov/">"U.S. National Geodetic Survey home page"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=U.S.+National+Geodetic+Survey+home+page&rft_id=http%3A%2F%2Fwww.ngs.noaa.gov%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ngs.noaa.gov/CORS-Proxy/Glossary/xml/NGS_Glossary.xml">"Geodetic Glossary"</a>. <a href="/wiki/U.S._National_Geodetic_Survey" title="U.S. National Geodetic Survey">United States National Geodetic Survey</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Geodetic+Glossary&rft.pub=United+States+National+Geodetic+Survey&rft_id=http%3A%2F%2Fwww.ngs.noaa.gov%2FCORS-Proxy%2FGlossary%2Fxml%2FNGS_Glossary.xml&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl">"Orthometric Height Conversion tool"</a>. <a href="/wiki/U.S._National_Geodetic_Survey" title="U.S. National Geodetic Survey">United States National Geodetic Survey</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Orthometric+Height+Conversion+tool&rft.pub=United+States+National+Geodetic+Survey&rft_id=http%3A%2F%2Fwww.ngs.noaa.gov%2Fcgi-bin%2FVERTCON%2Fvert_con.prl&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANorth+American+Vertical+Datum+of+1988" class="Z3988"></span></li></ul>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; 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