Last seen: April 9, 2026 5:20 pm
I referred to the ellipsoids: GR80 and WGS84 as same. Per NGS:"...Please note that the GRS80 and WGS84 [ellipsoids] are considered to be the same. Act...
Gotta keep up. 20 years of revisions, miss a few memos and then ..."Consequently, rigorously speaking, a transformation between NAD83 and WGS84 should...
The old WGS84 the ellipsoid and the WGS84 datum mixup. I'll never forgive them for naming them the same.WGS84 the ellipsoid is a correct designator. A...
JOHN NOLTON, post: 364350, member: 225 wrote: For: Larry ScottI just read your post and would like to comment on some things.1. Wild says that their ...
In a 1925 textbook "local attraction" was known to exist in astronomic Lat/long determination. And cited as an assumed 2" uncertainty, with no solutio...
For instance:Station 1 on mountainStation 2 in a valleyDistance between the two: 11.6 milesGeodetic Inverse calculation returns a 'forward' and 'back'...
Convergence is math. Laplace is not. Laplace is an error much like centering, leveling. NGS deflection database is a modeled estimate. So, you apply a...
Astro to geodetic is simplified Laplace. Geodetic to grid is convergence.So if you have a geodetic azimuths, from Astro observations, at both ends of ...
Yes, if you use an Astro azimuth (instead of grid) at annintial location, for subsequent azimuths, elsewhere, you would have to calculate and apply co...
I carefully measured a handful of angles. And then remeasured them a good while later.Yup, they're different - every time.But, if I round off to the n...
(any triangle has 6 elements. So, if know any 3 you can calculate the remaining 3)Apparently you can measure 5 elements. The distances to A are just a...
In Starnet you enter grid azimuths.And several azimuths is always better. If each one is 5-10" in error, hopefully, that would random error and Starne...
Remember it's Imagining the size of a second of arc.Nautical miles have had many definitions.A common value was 6080 ft, which was to approximate 1 mi...
And latitude is 1" äö 100 ft. Longitude is 1" äö 100' x cos(Lat)At 39å¡, 1" longitude äö 78 ftI have an old text with tables to convert feet of ...
It's always been: a minute = nautical mile. Nautical mile = 6080 ft äö 60 seconds Divide by 60 äö 1" äö 100 ftDivide by 100 äö 1 ft äö 0.01 ...
A T2 is an amazing instrument. What I saw in the results, just like the documentation said, the upper limit of subtense distance accuracy is user defi...
I'm familiar with DIN standards. A standard deviation of one angle is not mathematically significant. So (D/R)/2 = 0.8" has no real certainty. The pop...
Well, I didn't post the full precision of the resulting angles. And I indicated using a Lufkin Super highway 'chain' which is a tape. Along with a K&a...
I have been checking out distances by subtense. T2, 10-16 sets, SDEV usually 0.8", std err around 0.15".Day-to-day repeatability generally: 0.2-0.3 se...
leegreen, post: 362673, member: 2332 wrote: Larry,Not to disrespect RFC or yourself here. RFC is a newbie to surveying, and has learned all of his sur...