All kidding aside, I initially agreed with management on the validity of their argument, but the next day I reverted back to my original position on the subject. I mean really, how often do we have the convenience of checking into a published NGS azimuth mark? How often can we check into a known plat line? If the beginning and ending pairs of GPS points of an open traverse are properly post-processed they should be perfectly valid. Management is now standing firm on a single fifteen minute observation per point for traverse points and section corners.
They want to create some stability. Have some rules for the crews to follow.?ÿ
Still, why do they think an azimuth mark is the best control?
Still, why do they think an azimuth mark is the best control?
Those are my words. They just want something official like an NGS point.
I'm probably in the minority here, but I have never been a fan of the diamond traverse. It's only useful to me if my project absolutely requires a traverse closure (can count those projects on one hand), or for some weird reason I am unable to perform a least squares analysis.
Instead, I'll just perform two station setups (and two rounds of observations) at each control point, relevelling and recentering in between those two setups. This also gives me an opportunity to verify heights, or change them for an additional check, if vertical is critical. My preference is to switch backsight and foresight on the second setup to close the horizon, which gives me an immediate check on the first set of observations. If the horizon closure, distance or vertical deltas are unacceptable, it's easy to re-measure before moving up.
Still only requires one trip through the open traverse, gets you plenty of redundancy - without adding more unknown stations like a diamond traverse - and there's less chance of a blunder on sighting the wrong point immediately next to another one. Not to mention more blunder checks period.
Throw everything into a correctly weighted LSA and whammo, not only do you get most likely values for coordinates, but proper error estimates as well.
Tape the distances 2-8, etc. for additional checks.
Sounds like an efficient way to get redundancy. Re-centering (and releveling if not automatic), not just measuring twice, seems an important part of it.?ÿ I, too, fail to see the advantage of the diamond traverse over a double-measured (walking single direction) traverse.
I haven't done one in years because we mark timber lines with open traverse pin to pin. We close loops when setting a section corner but i think it makes less error to traverse to spots that see long shots across canyons as opposed to dozenzs of short turns in the S@%&.
I need a trial of this javad thing??? id make a video repeating one of my jobs and it might settle this pretty quick if it sits on 2 brass caps and it agrees with my line posts down in the S%@$ between them???
Oh yeah, boss said the new gun showed up this weekend. Team Nikon?????ÿ
@jed?ÿ
A video'd trial of any brand of GPS in those woods would be great.?ÿ?ÿ
@field-dog?ÿ ?ÿ exactly... and what happens with the new modernization and NGS doesn't even set or maintain physical monuments?
@jed?ÿ ?ÿ yep...?ÿ and using a "diamond" and "square" orientation for the flagging for the sight nails helps differentiate... or different color flagging.
@andy-j?ÿ
NGS hasn't set any monuments in years, not around here anyway. I think that the last hurrah in that department was around 1990.
hat happens with the new modernization and NGS doesn't even set or maintain physical monuments?
The new definition of official elevation will be GNSS tied to CORS, plus a gravity model to convert ellipsoidal height to orthometric.?ÿ If you want a physical mark, that will be up to you.
@jed?ÿ
Hope that Nikon works out, I found them great for deep woods work...compact, light and pretty tough too. Think I was using the Nivo...
@amksyr I think that's new info in this thread.?ÿ From what I understand it's not possible to adjust an open traverse without the first and last stations both known.?ÿ There would be no information to adjust to.?ÿ If adjustment is needed, I'd guess you have to close it by traversing back to the POB or make them known by taking static GNSS shots on each and conforming them to a known datum.
