<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:"Brush Script MT";
panose-1:3 6 8 2 4 4 6 7 3 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}
span.EmailStyle17
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.apple-converted-space
{mso-style-name:apple-converted-space;}
span.EmailStyle19
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle21
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>The North American Vertical Datum of 1988 (NAVD 88) is the vertical control datum established in 1991 by the minimum-constraint adjustment of the Canadian-Mexican-U.S. leveling observations. It held fixed the height of the primary tidal bench mark, referenced to the new International Great Lakes Datum of 1985 local mean sea level height value, at Father Point/Rimouski, Quebec, Canada. Additional tidal bench mark elevations were not used due to the demonstrated variations in sea surface topography, i.e., the fact that mean sea level is not the same equipotential surface at all tidal bench marks.<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><b><i><span style='font-size:12.0pt;color:black'>Tripp Corbin, MCP, CFM, GISP</span></i></b><b><span style='font-size:12.0pt;color:black'> </span></b><span style='font-size:12.0pt;color:black'>| Chief Executive Officer</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><b><span style='font-size:18.0pt;font-family:"Times New Roman","serif";color:#244061'><a href="http://www.egisassociates.com/"><span style='color:#244061;text-decoration:none'>eGIS Associates, Inc.</span></a></span></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><a href="mailto:tcorbin@egisassociates.com">tcorbin@egisassociates.com</a> | <a href="www.egisassociates.com">www.egisassociates.com</a> <o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>678-710-9710 ext 21 | 866-</span><span lang=EN style='color:#244061'>304-3864 Fax</span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>Esri Certified Trainer | Esri Certified Desktop Associate</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:black'><o:p></o:p></span></p></div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> shrug-l-bounces@lists.dep.state.fl.us [mailto:shrug-l-bounces@lists.dep.state.fl.us] <b>On Behalf Of </b>Sykes, John<br><b>Sent:</b> Tuesday, July 10, 2012 9:25 AM<br><b>To:</b> Thomas, Jim; shrug-l@lists.dep.state.fl.us<br><b>Subject:</b> shrug-l: RE: Elevation Unit Reference for NAVD88<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>Jim:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>NAVD88 is a datum. Elevations in NAVD88 relate to the NAD83 ellipsoid and has little relationship to local sea level. Therefore, “xx.xx ft (NAVD88)” would be the proper citation.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>I believe that elevations relating to local sea level would be listed as “xx.xx ft( AMSL)” which would refer to a local benchmark that has been surveyed to the local sea level. NOAA costal charts list the various sea level datums for a specific location, and the survey data is referenced to it. I might be wrong on the second point, it has been several years since I had to work with sea level data.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>Again, someone feel free to jump in on this, it has been a long time since I worked with sea level data (1999 in the Florida Keys).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><b><span style='font-size:24.0pt;font-family:"Brush Script MT";color:#1F497D'>-- John</span></b><span style='font-size:24.0pt;color:#1F497D'> <o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Please take a few minutes to share your comments on the service you received from the department by clicking on this link <a href="http://survey.dep.state.fl.us/?refemail=John.Sykes@dep.state.fl.us" target="_blank">DEP Customer Survey</a>.</span></em><span style='font-size:9.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a href="mailto:shrug-l-bounces@lists.dep.state.fl.us">shrug-l-bounces@lists.dep.state.fl.us</a> [<a href="mailto:shrug-l-bounces@lists.dep.state.fl.us">mailto:shrug-l-bounces@lists.dep.state.fl.us</a>] <b>On Behalf Of </b>Thomas, Jim<br><b>Sent:</b> Tuesday, July 10, 2012 8:50 AM<br><b>To:</b> <a href="mailto:shrug-l@lists.dep.state.fl.us">shrug-l@lists.dep.state.fl.us</a><br><b>Subject:</b> shrug-l: Elevation Unit Reference for NAVD88<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I all,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a survey question related to elevation units. Since NAVD88 <b>ZERO</b> and MSL <b>Zero</b> are not necessarily the same, is it wrong to express elevation units that reference NAVD88 as ‘FT AMSL’? Or is ‘ft’ more appropriate?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve seen data stored this way and I would like to suggest the appropriate unit. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='margin-bottom:10.0pt'><div><div><div class=MsoNormal><hr size=2 width="100%" noshade style='color:#008264' align=left></div></div></div></div><p class=MsoNormal style='margin-bottom:10.0pt'><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>Jim Thomas, GISP</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'> | GIS Analyst | </span><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>Golder Associates Inc.</span></b><b><span style='font-size:10.0pt;color:teal'> <br></span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>9428 Baymeadows Road, Suite 400, Jacksonville, Florida, USA 32256</span><span style='font-size:10.0pt;color:black'> <br></span><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>T: </span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>+1 (904) 363-3430 | </span><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>F: </span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>+1 (904) 363-3445 | </span><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>E: </span></b><a name=email></a><a href="mailto:jim_thomas@golder.com"><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>jim_thomas@golder.com</span></a><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'> | <a name=web></a><a href="http://www.golder.com/"><b><span style='color:black'>www.golder.com</span></b></a></span><b><span style='font-size:10.0pt;color:black'> <br></span></b><br><b><i><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:teal'>Work Safe, Home Safe</span></i></b><b><i><span style='font-size:10.0pt;color:teal'> <br></span></i></b><br><i><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:gray'>This email transmission is confidential and may contain proprietary information for the exclusive use of the intended recipient. Any use, distribution or copying of this transmission, other than by the intended recipient, is strictly prohibited. If you are not the intended recipient, please notify the sender and delete all copies. Electronic media is susceptible to unauthorized modification, deterioration, and incompatibility. Accordingly, the electronic media version of any work product may not be relied upon.</span></i><span style='font-size:7.5pt;color:gray'> <br></span><br><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:gray'>Please consider the environment before printing this email.</span></b><span style='font-size:10.0pt;color:gray'> </span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></body></html>