Don't know what you're talking about.
He is getting on state plane.?ÿ
That's the whole point, he is getting state plane on both ends of the traverse and putting the entire traverse on state plane.
This isn't difficult, no reason to make it difficult. State plane was designed just for this. Been doing similar calculations for more than forty years now,,,,,,,,lllllloooonnnnngggggggg before the button pushers showed up with black boxes.?ÿ
@rover83 Thats because you read. ?ÿNot everyone reads. Text books ngs publications. Go to further training. ?ÿStudy ask questions. ?ÿNot everyone does that. ?ÿAnd not every college course makes it through all the material to educate one on that. Example. ?ÿWhen I took advanced geodetic course in college. It used the NAD27 approach. ?ÿAlmost every person came out of that class not understanding the ellipsoid of nad83 in the grid vs geodetic calculations. Only reason I knew was because of the Defense Mapping School and reading more on my own. Things like geodesy for the layman othe publication. Attending ngs classes webinars ceu pdh. I agree that it??s plane if one studies all the material. I am a little slow so every-time i re read or dive in and study i get a little more. ?ÿI wish more people did pay attention but it is simply not reality. Sure some know the buzz words but like I mentioned above when you look at data and quickly identify that a scale factor doesn??t mean the same to everyone. ?ÿI like that you pointed out a site calibration scale. ?ÿGeezers we could discuss this disaster all day. Try a site calibration with 4 points almost in straight line with a .991xxxxxxxx and they call it good. Because residuals fell somewhat low or good enough. Fix that to 1 and you see how well gps observations met existing control. You are right on. Just remember not everyone takes the time to study and improve. Its a how fast can you get the data into the office kinda world. It checked in cad so its good. I enjoy reading your write ups. You do well in communication by writing. Would love to sit and pick your brain over dinner.
There isn't any need to calculate elevation or grid scales.
I haven't figured out a combined factor in many years....
If you don't compute the elevation factor, the grid factor, or the combined factor....what are you computing?
Straight from Michael Dennis at the NGS:
"Total linear distortion of grid (map) coordinates is a combination of distortion due to Earth
curvature and distortion due to ground height above the ellipsoid. In many areas, distortion due
to variation in ground height is greater than that due to curvature."
Ignoring either source of distortion is just poor practice, especially when we have readily available tools to compute both.
Been doing similar calculations for more than forty years now,,,,,,,,lllllloooonnnnngggggggg before the button pushers showed up with black boxes.
What is this fetish with calling anyone who uses a software program a button pusher? Do you use a pencil and paper without a calculator, and hand-comp the equations from the NOS NGS 5 every time you need a convergence angle or scale factor?
I've written programs in Matlab and Python to use those equations for various purposes, and I've checked them by calculator when my code was throwing some odd results, but I've never done them by hand because...why would I? I have better things to do with my time.
I've been doing this for nearly twenty years, and I've gotten more efficient in that time; I plan on continuing to do so.
I don't care whether someone relies upon software to do tedious calculations, I care whether they understand what that software program is doing.
@rover83?ÿ
Yes. I came to surveying terminology late and learned from NGS, books, you guys, GISers, trial and error, etc. Here's a snippet from a Data Sheet:
Notice there is a scale factor, an elevation factor, and a combined factor. There is no "elevation scale factor" nor "combined scale factor."
CG0981! - Elev Factor x Scale Factor = Combined Factor CG0981!SPC AZ E - 0.99974534 x 0.99990499 = 0.99965035 CG0981!SPC AZ C - 0.99974534 x 1.00016154 = 0.99990684 CG0981!UTM 12 - 0.99974534 x 0.99964263 = 0.99938806
Now a lot of this was determined by mathematicians, most of whom had never held a rod, stretched a tape or chain, or sighted a heliotrope.
But here's the thing. The scale factor is the ratio of an infinitesimal distance on a map projection to its corresponding infinitesimal distance on the reference ellipsoid. It is constant and calculable for any point whose geographic and/or map coordinates are known along with the map projection and the reference ellipsoid used. It depends on nothing other than mathematics. It is unaffected by crustal motion or other physical processes.
NCDOT road maps include the following notation:
These maps are smaller representations of the NC State Plane, which has an approximate scale of 1:1. The reference alludes to the fact that distance scales are not constant between every pair of points.
The elevation factor, on the other hand, measures the vertical distance between the earth's topographic surface and the reference ellipsoid at a point. Knowing the map or geographic coordinates of a point does not give enough information to calculate an elevation factor. Thus, although the elevation factor is a ratio, a mathematical quantity, it is not a "scale factor." It cannot be determined without reference to the topographical surface, a non-calculable quantity, and is thus not a scale factor.
The combined factor, the product of a scale factor and a non-scale factor, is likewise not a scale factor.
The terms "elevation scale factor" and "combined scale factor" are so embedded in surveying terminology that they now appear in equipment manuals. I think, and someone can probably find an example, that Michael Dennis has used one or the other or both terms in his 2022 papers.
It's interesting to note that "sea level factor" does not include the word "scale." In essence, it is used as a combined factor, as it converts between ground and map distances. Those old guys back when were far smarter than I am and they knew that the geoid and ellipsoid were different, but they didn't have sufficient measurements of the geoid to separate it out and NAD27 fit the US very well. The result is the same as assuming geoid height to be 0 everywhere.
So, it seems likely that inserting "scale" everywhere came about with or after NAD 83 and NAVD 88. Perhaps when that last old persnickety wordsmith at NGS dies off, scale will intrude every ratio in the Datasheets, or whatever replaces them.
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@mathteacher You have an attention for detail. You are another on this site I would love to sit with. Yes you are very much correct in how all the terminology that is used by manufacturers, instructors, even I blame myself many times on doing some type of verbiage to try and relate something in a way so someone gets a basic understanding that I know has no idea what goes on in the box. ?ÿMatLab is one awesome tool. I am not a coder type person but have used Malab to aid in speeding up task over time.?ÿ
Now back to bouncing across the field tedding hay. Its not easy keeping tractor straight as I try and educate myself as I farm. But what a great classroom. Fresh air bugs sunshine and reading an this site. If I had a good computer I would just sit down with a traverse set of data and write it all out for the calculations but my iPhone is about as good as it gets. I know the ngs pubs. One i have saved from before i was born I believe has some great examples for many calculations. I can??t think of the name. It shows the formulas and gives exams. Some ngs pubs give definitions and formulas but no examples. Not that is the point but a good easy to follow cheat sheat would probably help many.?ÿ
@rover83?ÿ
What in the world are you going on about?
This is simple, basic, easy.?ÿ
He is getting a SPC coordinate on the ends of a finished?ÿGROUND?ÿtraverse that's completed and adjusted. All that's needed is to inverse between the ground coordinates and the grid. That relationship is the scale factor.?ÿ
Holy moly, this isn't that difficult, what he heck is this about NGS books, Micheal Dennis, Matlab, Python, it's a word salad that's unneccessary for this simple, simple, simple SPC conversion. All the work is completed, he just needs a couple of points for translation and a couple of checks.?ÿ
This is SPC surveying in it's simple form, as it was designed to be done.?ÿ
It's 800' long!!!!!!!!!!!!
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Sounds like a reading comprehension problem to me, or maybe you're just being disingenuous.
I made it clear early on in the thread that a simple translation/rotation/scale may be warranted depending on the circumstances.
Later on, I was specifically responding to your implication that it is unnecessary to calculate grid, elevation, or combined factors at all and that people who do are "button pushers".
I quoted your own post for reference if you're having trouble following along. Clicking on the quoted text will take you to the origin post.
This thread is going in circles.
A ground traverse to SPC should??ve ended with 3-4 replies. It??s a straight forward transformation. HP41 survey pack could handle it. And it??s a small site.?ÿ
In defense of @mightymoe, this is what "those meddling kids" are listening to these days (get off my lawn!):
https://www.xyht.com/surveying/grid-ground-project/
?ÿ
Here is a example this traverse ran 3000 feet. GA is a Transfer Mercator. But it gives the equations and example data set. Fairly decent little article.?ÿ
Now, Moe, I admire you and your approach to surveying problem solving more than you will ever know. But having introduced Michael Dennis, books, and NGS into the conversation, I think I need to reply.
The relationship between grid and ground is not the scale factor, it's the combined factor. Refer to page 49 of NGS Manual 5 to see this in print.
For further information about the use of an overall project combined factor, read the traverse example beginning on page 53. For a quick look to confirm that the proper term is combined factor, skip to the top of page 58 where the project combined factor is computed.
I won't argue that the term "scale factor" has taken over and is now used to represent just about anything that doesn't square with ground observations. I will argue that distorting the nomenclature of a mathematically rigorous system hinders understanding, promotes unsound practices, and creates problems.
In learning how a complicated system works, mentors are great, books are great, and a combination of mentors and books is unbeatable. If you tell me something today, I read something contrary tonight, and we discuss the differences tomorrow, we both learn.
A grid factor in a Transverse Mercator projection will be determined by an easting, an elevation (height) scale factor will be determined by the height, the combined factor will only be correct for a distinct three dimensional point or the midpoint of a three dimensional line between two points.?ÿ
A project scale factor should be determined by comparing ground vs grid distances across the project. This can easily be accomplished by using quad sheet numbers or a program such as Google. Inversing resulting state plane values in a program such as TBC will give the ground and the grid distances. There is no need to calculate any combined factors across the project. The only point of a project scale factor is to simulate ground distances by applying a project scale factor to rise or lower the grid to a surface closer to ground. There is no need to survey before heading to the field to set-up a file to survey using a project scale factor.?ÿ
All that is interesting but the OP asked a simple question, can he rotate and translate his 800' survey into state plane. Of course he can, if he is given state plane coordinates on the two ends,,,,,it's a simple rotation. The Align command will easily do this in seconds in AutoCad. No doubt other programs have the same ability. Why this simple task has taken on such a discussion is beyond me. The OP already has a fixed distance from his survey so the scale factors from state plane discussion has no meaning. That simple math concept should be self-evident.?ÿ
By comparing his already fixed distance to state plane gird distance between the same two points the project will be automatically scaled.?ÿ
