Kent
Alright, a new function for Cousin Steve: A baseline of minimum understanding! Yay!
Kent
If you can get one old team to pull yer wagon there's no sense in ever using anything else (like a car), it just two complicated fer the ordinary *surveyor* to understand.
Kent
"The point is that in order to make a contribution, a geodetic reference system needs to be actually used by land surveyors who have a wide spectrum of other things to deal with in the course of surveying work. The system needs to be one that a surveyor of ordinary intelligence and experience can use with a minimum of effort but which performs the essential function for which a geodetic reference system is intended." Emphasis Mine.
Very well stated Kent, and I don't disagree with anything you said above.
The fact remains however, times and reference frames are a chang'n, and that's just a fact of life. With a minimal conceptual understanding (big geodetic picture), and a basic understanding of mapping projections, the average Land Surveyor should have no problem keeping up with modern geospatial technology, given the hardware & software tools available today.
Loyal
Kent
Leon - Huh?
Kent
If a surveyor's investment in tools and software stopped about 1990 it's going to be sort of difficult to get your head around some of the new things going on.
Anybody that's messed with things like Trimble TGO and ESRI ArcMap understands that projections are BASIC too mapping. There is more than one projection and they can be used for different problems. If your base data is in ECEF (a 3D system) you can switch projections as easy as changing your coat (if you understand how it works). I can't believe it's stall being debated! Obtuse never dies I suppose.
Loyal
I just hope that before the day comes that most of the content of this thread becomes more than esoteric gibberish to my everyday work, I will have enough sense to get a job selling shoes at Sears.
Steve
The basic concepts are actually quite simple, and it sounds a LOT more complicated than it really is.
Mike's whole point for this tread (I think), was to get a feel for just what folks really want and need in order to move forward.
Loyal
Loyal
I don't have a big problem with the basic concepts, I don't think. The problem I had when I first bought a GPS system was that I took every training class Topcon had and went to seminars about it at great expense with the simple question of "How do I measure with this thing?". The eggheads running the classes were not much help with that question. If I had graduated from a 4-year surveying curriculum would I have an easier time taking that hardware and making it do what I wanted it to do? Maybe so, but I don't think anybody ever expected a surveyor 50 years ago to understand why a metal tape made up of certain components expanded and contracted at certain temperatures, did they? It just did and we dealt with it accordingly.
As I said earlier, I admire the heck out of people like you that have the understanding to know what the equipment is doing and why and how to improve the technology and all that. I am not really interested in that and if that is what I signed up for when I became a surveyor, I made a big mistake.
Loyal
> I just hope that before the day comes that most of the content of this thread becomes more than esoteric gibberish to my everyday work, I will have enough sense to get a job selling shoes at Sears.
Cousin Steve, I think that it would be worthwhile trying to figure out what the stumbling block is for you. I'm not going to try to it this evening, but I'll keep you in mind. Practical application requires that surveyors like yourself be able to understand the system proposed for general use.
Cousin Kent
I promise not to do any large-scale geodetic survey networks this evening, so when you get it figured out, please let me know. I appreciate it.
Cousin Kent
> I promise not to do any large-scale geodetic survey networks this evening, so when you get it figured out, please let me know. I appreciate it.
Actually, my ambitions for you are a bit more modest. I think that in addition to doing the thousand other things that the work requires, you should be able to survey those mining claims you mentioned and report accurate positions for the claim corners in either a grid coordinate system projected from a geodetic reference system, such as the appropriate zone of the SPCS, or in NAD83 latitudes and longitudes. You should be able to evaluate and express the uncertainty in your results and have reasonable confidence in your assessment.
Cousin Kent
You don't have to answer right now, but why?
Invar tape for baselines adopted in early 20th Century
Howdy,
I do not intend to be obnoxious (though I am perhaps infected by the degeneration of this thread) BUT ...
You state: "Maybe so, but I don't think anybody ever expected a surveyor 50 years ago to understand why a metal tape made up of certain components expanded and contracted at certain temperatures, did they? It just did and we dealt with it accordingly. "
While I did not start working in the survey field 50 years ago, I do know that the use of invar tapes as well as earlier field methods to alleviate just the phenomenon you mention is much older than that. See for example the historic USC&GS photos showing early baseline measurement techniques involving shading and ice!
To alleviate my obnoxiousness I provide two (hopefully) interesting links related to the history of the US and Canadian geodetic surveying.
They are:
GSD Canada history timeline page. - see reference to 1921: Precise traverse in Canada
US NGS history timeline page - see reference to 1906 adoption of invar for measurement of triangulation baselines in US
I am still curious about how surveyors feel about other traditional elements included in geodesy courses (e.g. geodetic astronomy, the forward and inverse problems, etc.) .
Happy New Year.
Cheers,
DMM
Loyal
> Maybe so, but I don't think anybody ever expected a surveyor 50 years ago to understand why a metal tape made up of certain components expanded and contracted at certain temperatures, did they? It just did and we dealt with it accordingly.
wow! this statement is rather frightening
Cousin Kent
> You don't have to answer right now, but why?
1) Why is knowing the accurate latitudes and longitudes of boundary corners useful? Well, to name a few reasons:
- Can readily navigate to corner,
- Can facilitate search for boundary evidence,
- Readily compare position of boundary to other coordinated boundaries at small cost,
- Can overlay boundary on georeferenced aerial imagery for planning and reporting purposes.
- Is becoming commonly required by governmental organizations,
- Can coordinate boundary data with other activities such as seismic or other subsurface investigations using geodetic positioning,
2) Why should a land surveyor be able to demonstrate that his work is of a particular quality in terms of measurement and positioning?
- Desire to have defense against malpractice,
- Documentation of compliance with survey accuracy specifications such as ALTA/ACSM,
- Ability to demonstrate movement or alteration of boundary markers,
- Ability to combine older work with newer surveys tied to it.
Steve
I actually find it a little curious that your client DOESN'T want some form of Geodetic or Georeferenced Coordinates on those mining claims.
I've been involved in mineral exploration since the mid-1970s, and I don't recall very many instances where that wasn't part of the deliverable.
This is especially true today, when Exploration companies are using aerial photography, airborne geophysics, various space based remote sensing technologies, and pretty much tying everything together in some georeferenced coordinate system (usually UTM). They also use recreation grade GPS units (usually WAAS enabled) a lot for geologic mapping as well.
I have a friend that still stakes a lot of claims in Nevada, and he tells me that most of his clients actually send him UTM Coordinates on every claim corner that they want staked (which of course can cause problems if the client doesn't understand the grid-ground issues, which MOST DON'T).
Loyal
Loyal
> > Maybe so, but I don't think anybody ever expected a surveyor 50 years ago to understand why a metal tape made up of certain components expanded and contracted at certain temperatures, did they? It just did and we dealt with it accordingly.
>
> wow! this statement is rather frightening
Actually, in defense of Cousin Steven on this one, I understood him to be referring to the physics of materials, i.e. why different alloys have different cooefficients of thermal expansion. I'd have to reread some metallurgy to be able to explain what the Ni atoms in the Ni/Fe alloy known as Invar are doing that alters the physical properties of the alloy so dramatically.
Loyal
Maybe I've given the wrong impression of what I'm doing out there staking these claims. They are geo-referenced to the extent that I can go back to every one of the corners within a few tenths of the location that I'm reporting on the location notices and location certificates. Those claim locations are also interchangeable with lat/long's that I can co-ordinate with topo and data that the company sends me about stuff they have found in the field like a pit or some kind of geologic anomaly. If the fricking velocity of the North American continent has shifted a few millimeters, that's where I have to throw up my hands and let the experts handle it. I'll give you a call if that becomes important.
Steve
Sounds to me like you have a pretty good handle on it already.
Carry on...
Loyal
Loyal
> If the fricking velocity of the North American continent has shifted a few millimeters, that's where I have to throw up my hands and let the experts handle it. I
Yes, I think that is a typical land surveyor's reaction to the idea of using exclusively ITRF coordinates in surveying, i.e. coordinates that will change from month to month with crustal movement. I think it would be a solution looking for a problem.
