http://wiki.floodzilla.com/index.php?action=history&feed=atom&title=Vertical_Datum 2026-09-10T17:09:26Z Revision history for this page on the wiki MediaWiki 1.34.0 http://wiki.floodzilla.com/index.php?title=Vertical_Datum&diff=388&oldid=prev 2020-10-11T22:04:58Z

<p></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 22:04, 11 October 2020</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1" >Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Elevation measurements must be in reference to a vertical (sea level) datum. In the US most are tied to [[wikipedia:National_Geodetic_Vertical_Datum_of_1929|NGVD 29]] or [[wikipedia:North_American_Vertical_Datum_of_1988|NAVD 88]] (the numbers represent the years 1929 and 1988). Most elevations measured and reported today use NAVD 88. Unfortunately, the USGS still uses NGVD 29 as the base datum for [[USGS-22|Carnation]] and [[USGS-9|Duvall]] gages.  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Elevation measurements must be in reference to a vertical (sea level) datum. In the US most are tied to [[wikipedia:National_Geodetic_Vertical_Datum_of_1929|NGVD 29]] or [[wikipedia:North_American_Vertical_Datum_of_1988|NAVD 88]] (the numbers represent the years 1929 and 1988). Most elevations measured and reported today use NAVD 88. Unfortunately, the USGS still uses NGVD 29 as the base datum for [[USGS-22|Carnation]] and [[USGS-9|Duvall]] gages.  </div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>In the Snoqualmie Valley NGVD 29 elevations are 3.576 ft &quot;lower&quot; than NAVD 88 elevations according to [https://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl this conversion tool].</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>In the Snoqualmie Valley NGVD 29 elevations are 3.576 ft &quot;lower&quot; than NAVD 88 elevations according to [https://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl this conversion tool]<ins class="diffchange diffchange-inline">. In other words, add 3.576 ft to NGVD 29 elevations to convert them to NAVD 88 elevations</ins>.  </div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>We use NAVD 88 for the SVPA gages.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>We use NAVD 88 for the SVPA gages.</div></td></tr> <!-- diff cache key mediadb:diff::1.12:old-387:rev-388 --> </table>

GearyEppley http://wiki.floodzilla.com/index.php?title=Vertical_Datum&diff=387&oldid=prev 2020-10-11T22:03:49Z

<p>Created page with &quot;Elevation measurements must be in reference to a vertical (sea level) datum. In the US most are tied to <a href="https://en.wikipedia.org/wiki/National_Geodetic_Vertical_Datum_of_1929" class="extiw" title="wikipedia:National Geodetic Vertical Datum of 1929">NGVD 29</a> or wik...&quot;</p> <p><b>New page</b></p><div>Elevation measurements must be in reference to a vertical (sea level) datum. In the US most are tied to [[wikipedia:National_Geodetic_Vertical_Datum_of_1929|NGVD 29]] or [[wikipedia:North_American_Vertical_Datum_of_1988|NAVD 88]] (the numbers represent the years 1929 and 1988). Most elevations measured and reported today use NAVD 88. Unfortunately, the USGS still uses NGVD 29 as the base datum for [[USGS-22|Carnation]] and [[USGS-9|Duvall]] gages. <br /> <br /> In the Snoqualmie Valley NGVD 29 elevations are 3.576 ft &quot;lower&quot; than NAVD 88 elevations according to [https://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl this conversion tool].<br /> <br /> We use NAVD 88 for the SVPA gages.</div>

GearyEppley