Hi Stephen,
I'm not sure why you are so down on a coordinated cadastre (or moving towards one by ensuring all surveys are on the same grid north datum) but here is something I found within one Google search. It puts it more succinctly than I could have.
http://www.sla.gov.sg/htm/ser/ser0402.htm
The reasons listed there are:
- Establishing a homogeneous ISN network, enabling surveying to be more consistent
- Simplifying surveying procedures and documentation
- Enhancing the use of IT in surveying through E-submission
- Enabling a survey work to be carried out in a shorter time and at a reduced cost
- Enabling the use of Global Positioning System (GPS)
We have found that the fourth point is especially true. Whilst you guys are hunting for a datum to find reference/corner marks that are difficult to find, we have set up and found them (or discounted them as the case may be if they have been destroyed).
The time spent transferring coordinates or grid north datum onto your job is far outweighed by the time saved when you are hunting for that ellusive mark. It even goes as far as been able to quickly draft up the job in the office before the survey, export it to Google Earth and see which portions of the job (or marks) can be recorded with the GPS or not. Being able to have this picture helps immensely in job planning and as you know, a little bit of planning can save a lot of time in the field.
Initially if nothing is coordinated, I can see how some jobs may be slightly more expensive but with sun obs like Kent has demonstrated or facilities like http://www.ga.gov.au/earth-monitoring/geodesy/auspos-online-gps-processing-service.html which I think would work for you as well it is definitely not difficult or onerous to do. As I said earlier, the difference in under ten years here in Tasmania has completely changed how a job is planned and executed. The boundary definition skills have remained the same so the clients result hasn't changed, but the collection of data is now quicker so the client actually gets their jobs done quicker and our job is easier. It really is a win win situation.
Cheers
Seb
Not down on them at all. Just want to hear the arguments. I appreciate the response. I'm off for work, and will digest it later in the day.
Thanks,
Stephen
Just curious?
check your map, Kent. Corbin is in Virginia, NOT Maryland. maybe your basis of bearings does need calibration...
Just curious?
> No, more like this new projection that places Texas at correct scale:
I believe that projection is using a ESF (egocentric scale factor) that is overly inflated.
Okay Kent, I'll spell it out...
> >
>
> This isn't a Texas issue, but one of surveyors actually providing a professional service, which an independently reproducible basis of bearings is a part of. I mean, you survey in some standard units of length, don't you? You don't just spin some randomly chosen scale factor into the data collector because presumably your client actually wants to know the area of the tract you're surveying. Standard units means "independently reproducible" also.
Don't be silly Kent. You seem to lose sight of the fact that we work for our clients. It's not just some exercise in mathematical futility.
As commented above in this thread, the independently reproducible bearings will undoubtedly be used primarily by surveyors who want avoid the tedium of actually recovering & locating the existing monuments.
BTW, do you guys still charge extra to mark the client's property lines?
Okay Kent, I'll spell it out...
I'd agree that we work for our clients -- their needs ought to be met.I've heard it argued around here that independently reproducible bearings are what our clients ASSUME they are getting and that they'd be furious if they understood the basis of the bearings they see on the plans they pay for.
Kent, I beg to differ with you
It has been good for my sex life.
N
Okay Kent, I'll spell it out...
I'd agree that most clients think that they are getting independently reproducible bearings. However, they think that means that any and all compasses they can pick up at Walmart or that comes from a Cracker Jack box will show them were North is.
Frankly,
I always thought that the center of Texas was true north, and adjusted my north arrow accordingly. My only questions were exactly where you considered the exact Center of Texas. is it the geographic center of the state as a whole, the center of population, or the center of Austin?
Now you have me much more confused. I think I'll study on this a bit more.
Just curious?
> check your map, Kent. Corbin is in Virginia, NOT Maryland.
Just as a point of curiosity, is there any real difference between the Virginia and Maryland sides of the river other than a zip code?
Just curious?
Well, I'm sure that Maryland and Virginia look much larger in person. From a distance they sure look small, though.
Just curious?
None whatsoever.....I mean, unless you advocate using independently reproducible bearings.;-)
Interestingly, when the the 1993 and the 2012 surveys, each as its own independent system, are correlated using least squares, the orientation difference between the two is only one arc-second. Results are as follows:
(Course 1 = Pt 1 to 2 ... 6 = Pt 6 to 7)
[pre]
Point Residuals (ft)
No vN ... vE
1 - -0.010 ... 0.001
2 - -0.012 ... -0.009
3 - -0.006 ... -0.012
4 - -0.013 ... -0.006
5 - 0.004 ... 0.006
6 - 0.012 ... 0.011
7 - 0.026 ... 0.009
Translation:
dN = 0.0129
dE = -0.0036
Rotation:
theta = 00°00'01.0"
Scale: unity
[/pre]
Just curious?
> None whatsoever.....I mean, unless you advocate using independently reproducible bearings.
Do we really want to reproduce Maryland or Virginia?
Virgnina &cloudy days
> > check your map, Kent. Corbin is in Virginia, NOT Maryland.
>
> Just as a point of curiosity, is there any real difference between the Virginia and Maryland sides of the river other than a zip code?
Virginia is so beautiful they build big walls along all the interstates so people can't see it for free.
Kent, can we still do a sun shot if it's overcast? The crew is wondering if they should wait around till the clouds part so they can get a sun shot?
Virgnina &cloudy days
Perry,
Have you ever done a solar?
Honestly, just wondering.
o yea, email me your address and a small package of great value will arrive at your mail box.
I lost it from the gallon jug of sirple.
Swmbo is a voracious recycler.
Virgnina &cloudy days
> ....Kent, can we still do a sun shot if it's overcast? The crew is wondering if they should wait around till the clouds part so they can get a sun shot?
I recognize some "tongue-in=cheek" joking. But (regardless) I used to always try to emphasize to crews I worked with (in the past) that you should do a sun shot while the time is ripe and not just when you "want" to do it. The weather and time of day can play such a big factor. If you're out running traverse lines (and bring your clock and solar filter or prism) with you, and the sun is out and it's not too early or late for a measurement to the sun, do it then. Some of the guys would try to "schedule" to go out to do a sun-shot on a particular line on a particular day. Inevitably it might be overcast that day or some other glitch might occur.
That's one of the nice things about sun shots, you can do them during your working day while you're out on the job. We used to "schedule" nights to go out to shoot the stars. We would look at weather predictions, but you never knew if weather conditions might screw you up.
Virgnina &cloudy days
> Perry,
>
> Have you ever done a solar?
>
> Honestly, just wondering.
>
> o yea, email me your address and a small package of great value will arrive at your mail box.
> I lost it from the gallon jug of sirple.
> Swmbo is a voracious recycler.
Never done a solar. I did see a GPS once though.:-S
158 quebec road , lyman nh 03585
Virgnina &cloudy days
Even out here in big sky country that's a problem. I spent 3 days waiting for the sun to appear while doing a boundary at the north end of the great basin. The dang thing just wouldn't come out and play. What a mess I had rotating three days of work!
Virgnina &cloudy days
no sun shot for you, Perry. Kent's imagination and ego are both daydreaming on line.
