@rover83 well i am a usft guy but i just like the sound of it. ?ÿNo other reason other than it came to be in flow from previous units chains rods etc. It will still cause issues just like last year when i was following a plat that was in chains and the drafter said here is the deed and plat I can??t make it close. I grabbed the field folder headed home. The next morning as i was drinking coffee before heading to job site i was looking over everything and started laughing as it was hard to read but that not at the end made everything come into play. ?ÿChains and links. ?ÿActually the sucker was a very good measurer because I don??t think I missed any calls to hard points like axels or set pipe more than a tenth or so as i went around the property of that 40 plus acres and it was not a flat clear site but several hollars and ditches to cross and one area was swampy. Even the bearings computing internal angles were all very good compared to my 4 rounds with a 3 second robot and traverse kit. I found some blazed trees and other natural calls as well. Even the remanence of an old fence line he showed. Love those old surveyors they did exceptional work. I mean amazing work. Sometimes I think they took more care and pride than we do now days in our hurry up and its good enough society. Metes and bounds state. Other than the bad copy from courthouse he put enough calls and such that made following him very easy. ?ÿThe old farmer our client said his dad knew the man and he cut that out for him and he was getting an adjustment done to leave his kids some land .
Sorry, meant to include an emoji to indicate I was making fun of myself and other USA surveyors. No offense taken at all.
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As much as I would like for everything to be properly worked out in the planning and preparation stages, I admit that we still have to calibrate/localize on quite a few projects where we're going back and recovering legacy control. A big part of the problem is that there is often very little (often no) documentation on how it was adjusted and how good the absolute and relative accuracies are, so we just have to wing it when we show up. We had a habit of pushing out projected NEZs from RTK or RTN observations and holding them fixed for traverse and level adjustments, regardless of whether the vector precisions were 1cm or 10cm.
@rover83?ÿ
All of our newer projects are luckily being done in UTM with our local geoid and it makes things a lot easier, especially if control and monuments are destroyed in the future.?ÿ
It's older subdivisions and small jobs adjacent to stuff previously done locally that isn't done that way.
A proper analysis of elevations before calibration with GPS begins with using the Geoid Model and inspecting the vertical relationship between control points, doesn't matter if they are 88, 29 or an arbitrary 100 at a building finished floor.?ÿ
Using residuals in the calibration reports to accept and reject control points has been one of the vexing issues concerning calibrations. How to know if the ones you're accepting are the good ones and the ones rejected are the bad ones, reapplying the calibration in a different sequence may reverse the numbers, it depends how the numbers are assigned.
Working near the edge of a zone is one reason a proper projection is superior.?ÿ
In a calibration (Trimble version) the ground distance inverse is lost, I want to know the relationship between ground and grid, not possible in a Trimble calibration, the ground distance is not correct once the calibration is applied.?ÿ
I don't know if you work with Trimble equipment, but if you do, you should understand that Local Coordinates are not grid coordinates. In any of my TBC files, the Gobal Coordinate and Local Coordinate values will be identical for each point (NAD83). In the case of a calibrated file only one point will have identical Coordinate values, all the others will have an "adjusted" Local Coordinate value after being put through the calibration and that point value will be used in calculated inverses.?ÿ
Also, I'm at least 95% confident that your files are not WGS84 based.?ÿ
Again, if you're working in a calibration using Trimble take a look at the Local vs Global Coordinate, if what you see is fine with you then calibration should be fine with you.?ÿ
Go to this Trimble website:
https://help.trimblegeospatial.com/TrimbleAccess/latest/en/Site-calibration.htm#
Click on the "Software calibrations calculations" to get the fly-out to expand.
If you follow the flowchart, it should clarify what is happening and maybe turn on the lights about site calibrations.
One other key thing in site calibration as touched on is besides some of the settings that control scale etc is knowing what you are calibrating too. Is it assumed 1000,5000,100 like just old school surveying not a known projection or datum. In this case it??s wise to set your Trimble as no projection no datum. If its supposed to be a known datum like nad83 state plane or utm etc. this is where it gets critical to decide if the calibration is justified or not. I find more surveyors use rtk for control in east primary control than what i would have done when surveying in west which would have been static work. Rtk has come a long way but it is not as accurate and precise as static. ?ÿNow in some cases like a county control that is on state plane and you want to calibrate just because it seems faster or the office doesn??t have the resources or knowledge to do static. You can start out with that projection settings. ?ÿWhat i find sometimes is observing one point or holding one point makes the shift and brings all others in. You must check all around your site because no residuals with a one point. ?ÿSo make your checks. ?ÿI usually observe everything first and see if i can see what??s going on like shift or scale by someone and any rotation. But i have to remember i am only so accurate with rtk so experience comes into play and any knowledge or reports on how the control was done.?ÿ
also no matter if it is assumed or not no matter if you hold the site calibration or not. You still have all the raw rtk observations if done correctly. So even the assumed coordinates you have the ability to reverse everything and have a known datum like nad83 information as well as say the assumed site control. ?ÿIt is one of the benefits of using gps. So you can literally have two sets of coordinates. Use the known datum coordinates for your area to keep as control on the job next door in the future and if needed use your site control for the site. ?ÿ
With opus and network rtk these days that makes it so easy to get on datum is why some say it??s obsolete to site calibrate in general. Now there are times when an old survey or new one pops up on assumed coordinates and it just makes business sense to plop up a base station hit a here position and calibrate and do the work and be gone. ?ÿ Now even in these situations I usually log data at the base for sending to opus at very minimum. It takes no more time other than sending the file off in the end. This gives me the ability to build my control network in my geographic work areas. ?ÿ
just remember that surveying is more than just pushing a button ?ÿthere is mathematics involved ?ÿin every routine that need to be understood before performing the task ?ÿknowing what the software is doing is critical to not making a mistake ?ÿit is why I still use my calculator so much and read the white papers and help menu and manuals on things. ?ÿLS sais no resection??s allowed on jobs because he got burned many years ago ?ÿsais its black majic ?ÿi print and show him the two ways Trimble can compute a resection ?ÿits solid math its an easy read and it lets you know which way to perform it based on what you want to achieve and job requirements. I have been using resections since i was computing them by hand just using basic side angle side and bearings comps. But not a lot of statistics and a lot of room for a blunder. But sometimes its the best option ?ÿnow with data collectors it is my preferred option on jobs where I want the best set up for layout or mapping ?ÿout of every ones way. ?ÿSurveying is more than math as well. It??s knowing when good enough is good and understanding errors random systematic blunders ?ÿknowing law history using problem solving and more ?ÿalso using your spidey sences ?ÿthat sence you develop that sais something is not right even when all the math and procedures sais it is ?ÿyou know something is wrong. ?ÿ
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Topcon seems to retain both grid and ground points when doing a localization. At least you can cogo between them and they also have two different hz between the edm points and the rtn points.?ÿ
Topcon seems to retain both grid and ground points when doing a localization.
Every field software retains both sets of coordinates (geodetic and grid) used in the calibration/localization routine.
Grid coordinates come from plane geometry.
SPC/UTM coordinates are on a flat plane (via a mapping projection). Plane geometry = rectangular grid.
5000,5000,100 coordinates are on a flat plane too. Plane geometry = rectangular grid.
"Grid points" are a legitimate thing.
They can be on a mapping projection grid (SPC/UTM), or a 5000/5000 grid, or anything in between grid, as long as they are on a flat plane.
"Ground points" is a misnomer.
Topcon seems to retain both grid and ground points when doing a localization. At least you can cogo between them and they also have two different hz between the edm points and the rtn points.?ÿ
I'm not sure how Topcon does it. Trimble does not retain a set of ground and grid coordinates. What you see in Trimble ground inverse is a ground distance inverse based on the 3d numbers lat, long, height. I'm guessing Topcon does a similar calculation. When working in Coordinate systems it's important to set the unit to grid to be sure you're working with the XYZ numbers. One of the annoying things about my new DC is it seems to want to switch to ground inverses easily. I only want to look at those to be sure my XYZ numbers are "surface" coordinates.?ÿ
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When working in Coordinate systems it's important to set the unit to grid to be sure you're working with the XYZ numbers. One of the annoying things about my new DC is it seems to want to switch to ground inverses easily. I only want to look at those to be sure my XYZ numbers are "surface" coordinates.?ÿ
Stop. Just stop.
There is no such thing as a "grid" unit.
"XYZ numbers" are earth centered earth fixed cartesian coordinates. "XYZ numbers" are NOT "surface coordinates".
When working in Coordinate systems it's important to set the unit to grid to be sure you're working with the XYZ numbers. One of the annoying things about my new DC is it seems to want to switch to ground inverses easily. I only want to look at those to be sure my XYZ numbers are "surface" coordinates.?ÿ
Stop. Just stop.
There is no such thing as a "grid" unit.
"XYZ numbers" are earth centered earth fixed cartesian coordinates. "XYZ numbers" are NOT "surface coordinates".
Why does this trigger you so much, this is the routine in Trimble that allows you three settings: grid, ground and ellipsoid when inversing.
My response to the other poster was to let them know the ground inverse in Topcon was probably not the result of Topcon carrying two XYZ coordinate sets.?ÿ
In all my projects I want the grid, ground, slope and horizontal distances to be within a few PPM. At high elevations, which I only work in, our coordinate systems are scaled up to simulate the existing project ground surface within an acceptable PPM. They are typically called surface coordinates. You don't like that nomenclature, I get it, but it's not going anywhere.?ÿ
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Triggered? You want to see triggered, go read the thread about "lath vs stake"?!
Here is what bothers me:
Lazy, sloppy, imprecise vocabulary under the guise of "local vernacular" aka "nomenclature".
This is why so many laypeople don't understand a thing we surveyors do, surveying students have the impossible challenge of learning skills while contending with a constantly changing set of words/definitions, and many surveying professionals are more confused than students.
Geodesy, geometry, statistics, mathematics, etc. are all very precise subjects.
Surveyors seem to be the only group of people that can bastardize anything you throw at them, and then pass it along without "maintaining the highest of standards", and then wonder why our numbers are declining faster than political opinions.
Pride, stupidity, and stubborness is generally what got us here in the first place.
Our profession is not gaining the best new human talent because those smart individuals can see for themselves how the surveying profession promotes itself as a giant dumpster fire.
Hear, hear.
I don't give a damn where someone practices, we are all supposedly trained and educated on the hard sciences that make up the bulk of our technical work.
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...many surveying professionals are more confused than students.
Ain't that the truth.
Triggered? You want to see triggered, go read the thread about "lath vs stake"?!
Here is what bothers me:
Lazy, sloppy, imprecise vocabulary under the guise of "local vernacular" aka "nomenclature".
This is why so many laypeople don't understand a thing we surveyors do, surveying students have the impossible challenge of learning skills while contending with a constantly changing set of words/definitions, and many surveying professionals are more confused than students.
Geodesy, geometry, statistics, mathematics, etc. are all very precise subjects.
Surveyors seem to be the only group of people that can bastardize anything you throw at them, and then pass it along without "maintaining the highest of standards", and then wonder why our numbers are declining faster than political opinions.
Pride, stupidity, and stubborness is generally what got us here in the first place.
Our profession is not gaining the best new human talent because those smart individuals can see for themselves how the surveying profession promotes itself as a giant dumpster fire.
You are correct, we use lots of incorrect terms and euphemisms. Grid for "State Plane grid" when there are an infinite number of grids for any location. Heck, State Plane Grid is incorrect. Each state defined their grid systems and that's the term to be used. I will get a red line if I put Wyoming State Plane on a plat, it has to read the Wyoming Coordinate System. We say chain for measurement tape, gun for the total station or transit, the term Deed Staker is especially fingers on a chalk board for me. What that actually means is math staker.?ÿ
And you're very correct about XYZ coordinates. We don't really use ground coordinates, it's possible of course but each L, L pair would have an infinite number of ground coordinates depending on the elevation at that L,L.?ÿ
So, sometime ago DOT started to use what they and others call "Surface Coordinates" to mimic ground. This only works for small areas, a box about 5-10 miles, for their attempt to get close to measured along the ground to work. And believe me they really, really want to get as close as they can. They are obsessive about that. Is it correct? Not really, but it's not the worst term used out there. Do I mind, no, cause their coordinate systems, control networks, metadata, monuments are the best, no question about it. It makes it a pleasure to work with them, the most recent job I'm on I inverse between two points the ground horizontal distance is 647.567' and the grid horizontal distance (Trimble's term) is 647.565'. It might be .5654 and .5665, but whatever it's very close and it's what DOT wants.?ÿ
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Terminology aside, we do need clear terms for:
1.) Getting on to the proper LAT LON for a site. (and it's reciprocal SPC) OPUS, Javad DPOS are two items that come to mind. There are others too.
2.) Getting on to the proper LAT LON, (and it's reciprocal SPC) for a site, and getting a conversion from said SPC to the local system. This can include a number of parameters. Northing difference, Easting Difference, Rotation, Combined Scale factor, EW tilt, NS tilt.
EVERY surveyor needs to become fluent in those 2 items, and their practical use in the field.
Nate
Terminology aside, we do need clear terms for:
1.) Getting on to the proper LAT LON for a site. (and it's reciprocal SPC) OPUS, Javad DPOS are two items that come to mind. There are others too.
2.) Getting on to the proper LAT LON, (and it's reciprocal SPC) for a site, and getting a conversion from said SPC to the local system. This can include a number of parameters. Northing difference, Easting Difference, Rotation, Combined Scale factor, EW tilt, NS tilt.
EVERY surveyor needs to become fluent in those 2 items, and their practical use in the field.
Nate
Be careful State Plane Coordinate is an incorrect term, it's the State Coordinate System (SCS).
Just saying.?ÿ
Got to get everyone using the correct terms. ?????ÿ
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State Plane Coordinate is an incorrect term, it's the State Coordinate System (SCS).
In my experience the confusion is not whether the term "state" or "plane" is being used.
If someone says a coordinate system is "SPCS" or "SPC" or "[StateName] State Plane" (or in my case "Washington Plane Coordinate System") there should be zero confusion over what the projection parameters are, and how geodetic and grid values relate to each other.
Project coordinates are either:
1. In a grid projection.
or
2. Not in a grid projection.
In a grid projection there is a single northing and easting for a given latitude and longitude that is derived solely from applying the forward/reverse equations for the specified map projection i.e., LCC, TM, OM.
There's one way to get from here to there, and one way to get back. That's why they are so useful.
(Inverses between them might be very close to what someone measures "on the ground". Happens all the time in my area of operations. But they are still grid.)
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Confusion is introduced when someone says "state plane ground coordinates" or "localized state plane" or "calibrated SPCS", or other silliness, because those things don't exist. They require additional steps to warp, shift, or otherwise modify projected coordinates, making them....not projected grid coordinates any more.
If a project requires it, or someone wants to do those modifications, no sweat. But document exactly what is being done in what order to make the change, and don't refer to the project as being "in state plane" or "grid coordinates" any more.
State Plane Coordinate is an incorrect term, it's the State Coordinate System (SCS).
In my experience the confusion is not whether the term "state" or "plane" is being used.
If someone says a coordinate system is "SPCS" or "SPC" or "[StateName] State Plane" (or in my case "Washington Plane Coordinate System") there should be zero confusion over what the projection parameters are, and how geodetic and grid values relate to each other.
Project coordinates are either:
1. In a grid projection.
or
2. Not in a grid projection.
In a grid projection there is a single northing and easting for a given latitude and longitude that is derived solely from applying the forward/reverse equations for the specified map projection i.e., LCC, TM, OM.
There's one way to get from here to there, and one way to get back. That's why they are so useful.
(Inverses between them might be very close to what someone measures "on the ground". Happens all the time in my area of operations. But they are still grid.)
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Confusion is introduced when someone says "state plane ground coordinates" or "localized state plane" or "calibrated SPCS", or other silliness, because those things don't exist. They require additional steps to warp, shift, or otherwise modify projected coordinates, making them....not projected grid coordinates any more.
If a project requires it, or someone wants to do those modifications, no sweat. But document exactly what is being done in what order to make the change, and don't refer to the project as being "in state plane" or "grid coordinates" any more.
Also if you do it by state they define if it's US Feet or international
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The whole use of state plane scaled to ground is what makes my blood boil. ?ÿAs others have stated it is not and just because the numbers look similar doesn??t make them state plane . Just the same as looking at a plat that had nad83 on it. Nad83 is the datum so is that geodetic north on your plat or is it grid north and if grid north based on what. State plane zo e if so where is convergence angle etc etc. I am probably the poorest with words grammar on this site i do not deny that. But when i see just enough information to get someone in trouble on a plat it drives me bonkers . Because it implies we have to assume every other surveyor in our area is doing the same exact thing. Like me reading the requirements for a job. ?ÿ400 pages. 3rd page in 3 paragraph it sais blank will provide control on nad83 2011 xxstate plane coordinates and vertical shall be ngvd29 all control shall be withen x tolerance. ?ÿBut surveyor goes out well sends crew out. Gps a couple pairs traverse at ground scaled pairs to ground. ?ÿUsing geoid 12b so basically orthometric heights of navd88. I bring up the situation and they say well its close enough no problem. I give them the rough difference of whole project delta north delta east and difference between navd88 and ngvd29 and such. I just bite my bottom lip. ?ÿ
