FrancisH, post: 420576, member: 10211 wrote: yes, that's what I have been saying all along, you replace your vertical datum from WGS84 to EGM96 or EGM2008 ALL your RTK point elevation will SHIFT by a CONSTANT VALUE.
Duh, it's called inflating the ellipsoid. Clearly you don't have much experience or education it GNSS or Geodesy. You should really stop, we are all laughing at you. (unless that's what you are after?)
FrancisH, post: 420576, member: 10211 wrote: yes, that's what I have been saying all along, you replace your vertical datum from WGS84 to EGM96 or EGM2008 ALL your RTK point elevation will SHIFT by a CONSTANT VALUE. I think you have not even tried this or you would not even be here arguing with me.
Let me say this one more time, only a bit slower so you can follow along. Your method is an old stop-gap measure that makes the erroneous assumption that the geoid separation is a constant across a project. If you had taken any time in the last 20 years to educate yourself, you would have stopped using that archaic method.
In terms that you can understand, GEOID MODELS DO NOT CONSIST OF A CONSTANT GEOID SEPARATION!
In the US, the horizontal datum and realization normally used is NAD83(2011). Coupling it with the NGS GEOID12B model will generate NAVD88 referenced elevations.
I use Leica equipment and software. In Leica LGO, the user can create various geoid models. For projects in which I want to save and store NAVD88 elevations in the field, I load GEOID12B onto the rover receiver's flash card. LGO permits the user to save only a portion of the geoid model if there are space limitations with the flash card, using the "Create Geoid Model Field File" function. The rover, after obtaining a position will use the equation that GeeOddMike so kindly provided earlier in this thread to compute the NAVD88 elevation from the ellipsoid height and geoid separation obtained from the loaded GEOID12B model.
The other method is to save and store the ellipsoid heights on the rover flash card, download the raw data (both base and rover) into LGO, apply the "Compute Geoid Separations" function in LGO to the project and PRESTO, the ortho heights (NAVD88) and geoid separations are computed for each rover position and the base station. The geoid separations won't be the same!
I'm certain that this will generate a few lines of "haha" from you, but that's okay. I know this is a game of Whack-A-Mole with your FrancisH. Troll on.
I will make only two comments to this thread.
1. FrancisH is a good example of why PDHs are required for a PLS.
2. Quote from an old friend and lifetime hydro surveyor. "Water covers a multitude of sins".
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I'm not buying into the argument. All I want to say is this site has been a fantastic resource for me for a few years now. Polite, learned and eager to help bunch of surveyors. I feel disappointed knowing that someone is using this site in such an antagonistic way. Very disappointing. Francis H, the members of this site deserve much more respect.
I will say it again folks: You have been sucked into a battle of wits with an unarmed opponent.....or a troll.
As mattb said above, this site is too valuable of a resource, full of great members bringing vast knowledge and experience in all disciplines of surveying from virtually around the globe to spend any time arguing with, or trying to educate FrancisH or anyone like him. Just ignore him and move on. When he pops up spewing his ignorance in another thread, ignore him there as well. He has nothing positive to contribute and has no interest in learning. He is a complete waste of time.
That said, there has been some excellent information shared in this thread.
FrancisH - I never made any reference to the leveled vertical network in Indonesia - my response was about the lack of realization of the WGS 84 reference system. Since the Indonesian archipelago consists of thousands of islands the question would be what is the specific origin of the heights you are using - not just saying MSL, but rather the specific tide station from which the heights were derived, the length of time of the tidal observations (how many years) and the epoch of how those values may or may not have been adjusted into a consistent framework. Even then those realizations can be impacted by variations in local/regional crustal motion. Depending on the nature of the tidal range variability due to local hydrodynamics the surface of local mean sea level can vary considerably at any given location with respect to the origin of the local vertical datum. You may want to review the excellent paper on the Indonesian vertical datum written by Adolfientje Kasenda -- "HIGH PRECISION GEOID FOR MODERNIZATION OF
HEIGHT SYSTEMS IN INDONESIA". Even thought it's 25 years old it does a good job of describing some of the inherent problems faced in determining a consistent height system for the country.
SPMPLS, post: 420624, member: 11785 wrote: I will say it again folks: You have been sucked into a battle of wits with an unarmed opponent.....or a troll.
As mattb said above, this site is too valuable of a resource, full of great members bringing vast knowledge and experience in all disciplines of surveying from virtually around the globe to spend any time arguing with, or trying to educate FrancisH or anyone like him. Just ignore him and move on. When he pops up spewing his ignorance in another thread, ignore him there as well. He has nothing positive to contribute and has no interest in learning. He is a complete waste of time.
That said, there has been some excellent information shared in this thread.
While i concur in general terms, it is excellent training for dealing with 'small bucket' students.
You guys really need to put you know who on your ignore list. It seems like almost everything he writes is a troll. Please don't take the bait.
I wonder if there's an NGS utility out there somewhere that given a geiod model (such as GEOID12B) and geographic area will give you an indication of the local geoid minima, maxima, slope, etc. Or for visualization, a shaded 3D plot. Or perhaps the ability to zoom way in from the existing national and/or regional shaded and colored plots on as shown on the NGS GEOIDx web page down to square degree areas.
Bill93, post: 420544, member: 87 wrote: Please explain. I thought the most recent official update was Geoid12B several years ago, with a preliminary later one available for examination but not adopted.
Sorry, I forgot to turn on the sarcasam button.
We can explain it to him all day long. We cant understand it for him...
In terms that you can understand, GEOID MODELS DO NOT CONSIST OF A CONSTANT GEOID SEPARATION!
maybe if you had even taken a few minutes in your 20 years of "vast experience" to post process some gps data using both WGS84 & EGM96 or EGM2008 or whatever geoid model you prefer and see if the results in elevation has a constant factor you would realize what I am talking about.
Have you done that? I mean even done some post processing? Because up to now, you have not even told us what software you are using.
I am talking about RESULTS FROM GNSS SOLUTIONS the software. hahahahahah I just came to realize maybe most of the so called "experts" here are just paper experts.
hahahahahahha
hahahahaah all talk.
Duh, it's called inflating the ellipsoid. Clearly you don't have much experience or education it GNSS or Geodesy. You should really stop, we are all laughing at you. (unless that's what you are after?)
huh??? hahahahh inflating the ellipsoid??? wow ahahahahahh really? you could inflate a mathematical model???? hahahhahahaha
talk talk talk.....
I never made any reference to the leveled vertical network in Indonesia - my response was about the lack of realization of the WGS 84 reference system. Since the Indonesian archipelago consists of thousands of islands the question would be what is the specific origin of the heights you are using - not just saying MSL, but rather the specific tide station from which the heights were derived, the length of time of the tidal observations (how many years) and the epoch of how those values may or may not have been adjusted into a consistent framework. Even then those realizations can be impacted by variations in local/regional crustal motion. Depending on the nature of the tidal range variability due to local hydrodynamics the surface of local mean sea level can vary considerably at any given location with respect to the origin of the local vertical datum. You may want to review the excellent paper on the Indonesian vertical datum written by Adolfientje Kasenda -- "HIGH PRECISION GEOID FOR MODERNIZATION OF
HEIGHT SYSTEMS IN INDONESIA". Even thought it's 25 years old it does a good job of describing some of the inherent problems faced in determining a consistent height system for the country.
wow so much highly technical terms thrown in there....
MEAN SEA LEVEL is a technical term to describe the mean between high and low water at a particular location. Indonesia even with its 1000 islands is no different from any other country in the world with respect to mean sea level values because all other countries are considered also as an island. There is no difference in mean sea level observation techniques in Indonesia and another country. It is still based on tidal observation for 19 years. And you call yourself a Chief of Geodesy???? Really???You did not know this basic fact about MSL observation????
We can explain it to him all day long. We cant understand it for him...
well there is this adage, if you can't explain it to a 5th grader something ...then maybe you yourself don't understand what that something is????
hahahhahahahaha
Sorry, I forgot to turn on the sarcasam button.
ahahahhahahah busted.....No I think you really believed what you previously said...
hahahahhahahaha
FrancisH, post: 420728, member: 10211 wrote: well there is this adage, if you can't explain it to a 5th grader something ...then maybe you yourself don't understand what that something is????
hahahhahahahaha
I was pretty sure i had explained it to a 5th grader. No worries, you'll get there some day...
I was pretty sure i had explained it to a 5th grader. No worries, you'll get there some day...
actually all you did was say that you were an "expert", an expert really would have no need to say that he was an "expert" in the first place.....
hahahahhahaha
I finally found the Ignore button.
Jim Frame, post: 420736, member: 10 wrote: I finally found the Ignore button.
Ah come on Jim, it's like watching a one man Gong Show.
😉
Loyal, post: 420738, member: 228 wrote: Ah come on Jim, it's like watching a one man Gong Show.
It was a couple too many gongs for my taste.