<div class="gmail_quote">2012/1/14 Michal Seidl <span dir="ltr"><<a href="mailto:michal.seidl@gmail.com">michal.seidl@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- Mikael Rittri explanation helps me a lot, I was really for a moment<br>
confused by Frank's one<br></blockquote><div><br></div><div>Mikael's clarification was, indeed, excellent and useful</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- Joaquim formula h = H-N is OK. But as Frank said +geoidgrids is only<br>
name and can be used for other height correction which is exactly my<br>
situation.<br></blockquote><div><br></div><div>But please note that Wikipedia and leading geodetic textbooks (Hoffmann-Wellenhof & Moritz: Physical Geodesy, as well as Torge: Geodesy) use a different notation:</div><div>
<br></div><div>h: height above ellipsoid</div><div>H: orthometric height (which to an excellent approximation is equivalent to the height above the geoid)</div><div><br></div><div>Hence: h = N + H</div><div><br></div><div>
So following Joaquim's suggestion of +H and +h options is quite risky. Out of context you can never be sure what is meant by H and h.</div><div><br></div><div>/Thomas</div><div><br></div></div>