Thanks for the feedback folks. Still lots for me to learn on this topic
Shawn Billings, post: 416606, member: 6521 wrote: I don't worry about stating how bearings were established. I see the statement determined by "static GPS" or determined by "OPUS observations", etc, pretty routinely. But I never see anyone state "distances determined by Leica total station TPS-1200" or "distances reduced to horizontal Carlson SurvCE".
If my work is tied to State Plane, my standard statement is:
Bearings related to Grid North for the Texas Coordinate System of 1983, North Central Zone. Convergence at POB: +1å¡58'43".Most of the time my work is tied to a local grid system with geodetic North at the origin of the system so my standard statement is:
Bearings related to a local grid having an origin of North Latitude 32å¡12'34.5678" and West Longitude 94å¡12'34.5678". Convergence at POB: -00å¡00'17".Whether the bearings are from an inverse of two coordinates determined by OPUS or by some post processing software or by RTK or by Polaris or Solar observation of by gyroscope is of less consequence in my opinion.
According to one program presenter Shawn you are doing everything right but you have to relate it to a certain monumented line on the plat. For what reason I do not know or understand, what you are doing seems sufficient to me.
MightyMoe, post: 416712, member: 700 wrote: Either the survey is "true north" or a grid, if it's "true north" it's highly unusual unless you are a BLM surveyor,,, if it's grid then define it, either a SPC, UTM, LDP, record between know points, the choices are infinite, GPS is an aside to the process.
I see the term True North a lot, never liked to use it, much prefer Astronomic North as I have seen True be so many different things
Bushwhacker, post: 416793, member: 10727 wrote: I see the term True North a lot, never liked to use it, much prefer Astronomic North as I have seen True be so many different things
Perhaps youve seen folks misuse the term True North, but it has one very well estsblished meaning to Surveyors.
Bushwhacker, post: 416792, member: 10727 wrote: According to one program presenter Shawn you are doing everything right but you have to relate it to a certain monumented line on the plat. For what reason I do not know or understand, what you are doing seems sufficient to me.
Actually, that isn't what the present rule says, which is as follows:
RULE å¤663.19 Survey Drawing/Written/Description/Report
(c) Courses shall be referenced by notation upon the survey drawing to an identifiable and monumented line or an established geodetic system for directional control.
It is a fair question whether some custom map projection is "an established geodetic system" in the same sense that the Texas Coordinate System of 1983 is, of course, but otherwise mentioning the system is entirely adequate.
Kent McMillan, post: 416812, member: 3 wrote: Actually, that isn't what the present rule says, which is as follows:
RULE å¤663.19 Survey Drawing/Written/Description/Report
(c) Courses shall be referenced by notation upon the survey drawing to an identifiable and monumented line or an established geodetic system for directional control.
It is a fair question whether some custom map projection is "an established geodetic system" in the same sense that the Texas Coordinate System of 1983 is, of course, but otherwise mentioning the system is entirely adequate.
I didn't say the rules said that. i said a presenter said that.
Bushwhacker, post: 416836, member: 10727 wrote: I didn't say the rules said that. i said a presenter said that.
Well, presenters at CEU seminars say all sorts of things, but the board rules are what to pay attention to.
One of the wackier things I see on some maps of Texas surveyors is a note identifying some pair of markers as "Controlling Monuments", as if they are the only ones on the map, when in fact the map shows half a dozen or more monuments that the surveyor considered to control various boundaries. That misuse of the concept of controlling monuments has to also be the handiwork of some seminar presenter somewhere. Otherwise, it's so bizarre that it could not have spontaneously occurred to multiple sureyors in various places.
Bushwhacker, post: 416836, member: 10727 wrote: I didn't say the rules said that. i said a presenter said that.
There was a time that the rules didn't have the part about geodetic systems and only mentioned the part about the line.
Bushwhacker, post: 416793, member: 10727 wrote: I see the term True North a lot, never liked to use it, much prefer Astronomic North as I have seen True be so many different things
Hence the quotes around "true north", I haven't discussed with the BLM guys what "true north" means on their plats in the days of GPS, but I suspect it means geodetic north. Of course the important thing are the lines of constant bearings when surveying "true".
Shawn Billings, post: 416841, member: 6521 wrote: There was a time that the rules didn't have the part about geodetic systems and only mentioned the part about the line.
Actually, what the earlier version of TBPLS rule RULE å¤663.19 provided was that:
"(4) Courses shall be referenced by notation upon the survey plat to an identifiable line for directional control."
Grid North of the Texas Coordinate System, Astronomic North, and Geodetic North are, of course, all identifiable lines at every point on a survey. The modification of the language to explicitly reference "an established geodetic system" doesn't really add anything to the meaning of the rule.
Kent McMillan, post: 416837, member: 3 wrote: Well, presenters at CEU seminars say all sorts of things, but the board rules are what to pay attention to.
One of the wackier things I see on some maps of Texas surveyors is a note identifying some pair of markers as "Controlling Monuments", as if they are the only ones on the map, when in fact the map shows half a dozen or more monuments that the surveyor considered to control various boundaries. That misuse of the concept of controlling monuments has to also be the handiwork of some seminar presenter somewhere. Otherwise, it's so bizarre that it could not have spontaneously occurred to multiple sureyors in various places.
Same Presenter
MightyMoe, post: 416842, member: 700 wrote: Hence the quotes around "true north", I haven't discussed with the BLM guys what "true north" means on their plats in the days of GPS, but I suspect it means geodetic north. Of course the important thing are the lines of constant bearings when surveying "true".
The differnce between astronomic and geodetic north is so small for anywhere in the United States is doesn't matter.
aliquot, post: 416895, member: 2486 wrote: The differnce between astronomic and geodetic north is so small for anywhere in the United States is doesn't matter.
Most recent stated "true" surveys are actually grid surveys, with "true" determined somewhere close to the survey, probably using GPS these days. I don't know anyone doing solars anymore like I used to do all the time. Solars had more error in them than the geodetic vs. Astronomic difference.
aliquot, post: 416672, member: 2486 wrote: Are you reporting state plane distances on boundary surveys?
You can't rotate a state plane drawing to get geodetic bearings. A line of constant state plane bearing has a constantly changing geodetic bearing.
You can do it pretty well, if it is a lot 20 ft EW X 200' NS.
(Bad joke!)
🙂
thebionicman, post: 416805, member: 8136 wrote: Perhaps youve seen folks misuse the term True North, but it has one very well estsblished meaning to Surveyors.
Mr. Bionic,
If I retrace a survey, that says BOB: True North, and I find 5 surveys, spanning 3 miles E-W, by that same surveyor, and enough lines in common are shown, an all 5 plats are in FACT on the same, BOB then, it is obvious at face value that their BOB is being treated as though its the same... But that it's not TRUE NORTH, except maybe at 1 place in the whole network. Also, i have SEEN where the actual surveyor had used 3 base sites, and assumed they were the same BOB, not understanding convergence.... It's a mess!
MightyMoe, post: 416896, member: 700 wrote: Most recent stated "true" surveys are actually grid surveys, with "true" determined somewhere close to the survey, probably using GPS these days. I don't know anyone doing solars anymore like I used to do all the time. Solars had more error in them than the geodetic vs. Astronomic difference.
You are right abut most recent surveys misusing the term true north. GPS is a much easier way to actualy survery on geodetic bearing than taking a solar.
I don't really understand why we are still usin state plane. It was very usefull when we had to do computations by hand, but now most software can handle geodetic calculations. Why are we still trying to flatten the earth. We loose precision and introduce more chance for errors with scale factors, different feet, ect..
One thing to watch out for is people who try to do PLSS proportions or replace a corner from a bearing object in state plane or local grid.
aliquot, post: 417040, member: 2486 wrote: You are right abut most recent surveys misusing the term true north. GPS is a much easier way to actualy survery on geodetic bearing than taking a solar.
I don't really understand why we are still usin state plane. It was very usefull when we had to do computations by hand, but now most software can handle geodetic calculations. Why are we still trying to flatten the earth. We loose precision and introduce more chance for errors with scale factors, different feet, ect..
One thing to watch out for is people who try to do PLSS proportions or replace a corner from a bearing object in state plane or local grid.
A proration can get really messed up in state plane, I've seen it more than a few times:(
