<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><b class=""><font size="4" class="">Reminder. Registration still open. </font></b><div class=""><div class=""><br class=""></div><div class=""><p style="margin: 11px 0px; padding: 0px; border: 0px; outline: 0px; color: rgb(51, 51, 51); font-family: Arial, Helvetica, Geneva, sans-serif; line-height: 16.7999992370605px; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial;" class=""><strong style="margin: 0px; padding: 0px; border: 0px; outline: 0px; background-color: transparent; background-position: initial initial; background-repeat: initial initial;" class=""><a href="https://attendee.gotowebinar.com/register/4120367411599363330" class="">https://attendee.gotowebinar.com/register/4120367411599363330</a></strong></p><div class=""><b style="font-size: 14px;" class="">Relationship of and Transformations Between most Common Reference Frames used in the U.S.</b></div><p style="margin: 11px 0px; padding: 0px; border: 0px; outline: 0px; color: rgb(51, 51, 51); font-family: Arial, Helvetica, Geneva, sans-serif; line-height: 16.7999992370605px; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial;" class=""><strong style="margin: 0px; padding: 0px; border: 0px; outline: 0px; background-color: transparent; background-position: initial initial; background-repeat: initial initial;" class="">Abstract:</strong> This presentation will cover the relationship of and transformations between the several geometric and vertical geodetic reference frames most commonly used in the United States. These include: The North American Datum of 1927 (NAD 27), the North American Datum of 1983 (NAD 83), the International Terrestrial Reference Frame (ITRF), the World Geodetic System of 1984 (WGS 84), the National Geodetic Vertical Datum of 1929 (NGVD 29) and the North American Vertical Datum of 1988 (NAVD). The program will specifically examine tools such as the gridded utilities NADCON and VERTCON developed by the National Geodetic Survey (NGS), as well as the commonly used 3-parameter abridged Molodensky transformations originally computed by the U.S. Defense Mapping Agency (DMA) and the more rigorous 14-parameter transformations supported by the NGS utility HTDP (Horizontal Time Dependent Positioning).</p><p style="margin: 11px 0px; padding: 0px; border: 0px; outline: 0px; color: rgb(51, 51, 51); font-family: Arial, Helvetica, Geneva, sans-serif; line-height: 16.7999992370605px; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial;" class=""><strong style="margin: 0px; padding: 0px; border: 0px; outline: 0px; background-color: transparent; background-position: initial initial; background-repeat: initial initial;" class="">Bio:</strong> Dave Doyle joined the National Geodetic Survey in 1972, and held the position of chief geodetic surveyor for twelve years prior to his retirement in January 2013. He was responsible for the development, technical design and management of plans and programs that enhanced the United States National Spatial Reference System. During his career with NGS his experiences included all phases of geodetic triangulation, astronomic positioning, leveling, GPS data collection, data analysis, datum transformations, network adjustments, data publication and outreach in the form of seminars, workshops and webinars. His efforts also included extensive activities to direct and coordinate the modernization of national geodetic reference frames in countries in Africa, Central, Caribbean and South America, Eastern Europe and the Pacific.</p><p style="margin: 11px 0px; padding: 0px; border: 0px; outline: 0px; color: rgb(51, 51, 51); font-family: Arial, Helvetica, Geneva, sans-serif; line-height: 16.7999992370605px; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial;" class="">Mr. Doyle is a Past President of the American Association for Geodetic Surveying, a Fellow member of the American Congress on Surveying and Mapping, has served on the U.S. delegation to the International Federation of Surveyors and is an active member of the District of Columbia, Maryland and Virginia professional surveyors associations.</p>
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