Geodic Correction: Tripmaster

[nyer]

When I set Geodic Correction off, I get very low values for altitude. When I set it to the default value of 48, I get even lower values. Using trial and error I have determined that the 'correct' value for me (location Orange County, California) is -27 (my altitude display is in feet, in case it matters). Is there some place where I can find the correct geodic correction values for various places? I am assuming that the geodic correction values will be different in different places. We have a few SoCalers here. What value do you use?

 

[runarg]

If your TomTom does not have a SirfStarIII chip (the GO300 does not) yo have to correct for the Geoid. The correction is different for different places on the earth, and that makes it difficult. The newer TomToms with a SirfStarIII chip calculates the Geoid inside the chip. Yoy can find the Geoid for any place here:

http://sps.unavco.org/geoid/

 

[nyer]

runarg, thank you very much. I have been looking for an easy to use site like the one you provided the link to. Thank you once again. I found that my adjustment is almost -34.5 (rather than the -29 that I had initially guessed).