FL/GA PLS., post: 428590, member: 379 wrote: They actually admitted an error? (a miracle) 😉
Just as in any organization all previous errors were most assuredly because of someone that was no longer employed there...;)
The series of mistakes I made was when working for a company of button pushers that gave instructions and being the designated human robot IMan was expected to perform miracles.
They always seemed to do things in reverse, like staking out a small box and then setting universal sized control from the small box.
It was a daily thing for the PC to have me BS a tack 14ft away and turn a 90?ø angle and shoot in a control point 250ft away.
My daily words were "I know how to do my job very well, however I have been ordered to do what you say without questioning your reasons why".
paden cash, post: 428549, member: 20 wrote: 1934 USGS disc
The 1934 disk at the Norman depot and a line of bench marks along the tracks were by the US Coast and Geodetic Survey (US C&GS), the predecessor name of the National Geodetic Survey, and NOT the US Geological Survey (USGS).
If it was reset or has a 1-ft blunder, there is no indication on the data sheet. Perhaps this needs to be rechecked and reported?
https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=FJ0332
(not my photo)
Bill93, post: 428667, member: 87 wrote: The 1934 disk at the Norman depot and a line of bench marks along the tracks were by the US Coast and Geodetic Survey (US C&GS), the predecessor name of the National Geodetic Survey, and NOT the US Geological Survey (USGS).
If it was reset or has a 1-ft blunder, there is no indication on the data sheet. Perhaps this needs to be rechecked and reported?
https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=FJ0332(not my photo)
You are correct Bill. This and the other recoverable D series BMs up and down the tracks were the BMs we attempted to reconcile with the FEMA RMs. Only one of the FEMA RMs was recovered at the time and THAT datum disagreed with these USC&G monuments by 1 foot. At that time the powers-that- be (my employer and the City engineering department) decided to maintain the FEMA datum and disregard these 1934 monuments since the FEMA hydrology of the area appeared to have been calculated from the datum that was in error by 1'. That was the mistake that was rectified just a few years ago and make the FEMA panels reflect elevations more closely tied to the USC&G datum (adjusted to NAVD88). I merely ran about 12 miles of levels just to be told it wasn't necessary. 🙁
Sooo nowadays the FEMA FIRM panels do fit this BM in the wall of the Norman Depot, whereas in 1991 the bastard FEMA datum (that we inadvertently perpetuated) differed by a foot. Although this new "adjustment" was probably for the better, the redrawn floodplains raised a foot and disturbed a lot of private property that had previously been shown as above the BFE. There were a few mad folks around town believe me.
Sorry for the confusion. Here's a pic of the location of the "bad" BM listed by FEMA on an old panel that was actually the reset, not the disc in the wall of the depot, and its proximity to the closest 1934 BM. How they ever wound up 1' different is a story lost to the ages. I didn't think it was a good idea at the time to ignore the 1934 monuments, but my boss and the folks at the City did...it came back and bit everybody in the butt 25 years later.
I'd love to mention something that I screwed up royally, but was drawing a blank. The one thing that comes to mind was in the course of running a division line across a ranch 25 years ago in connection with a partition. The line itself was a snap. It ran for about three miles and had only two or three angle points, dividing a tract of about 5,000 acres into two smaller parts. Time was short and the terrain allowed it, so the control for the division line was surveyed via long radial ties from a point on a hill. That actually worked brilliantly as I discovered when I returned years later with GPS to tie some of the brass tablets in concrete at the angle points on the division line. Analysis of errors in Star*Net back in 1992 said that the errors should be within certain limits and - lo and behold - it turned out that they were.
The ranch had been assembled from more than about fifteen metes and bounds tracts out of several different land grants and one of the problems with writing the description of the division line was connecting to enough original corners of those tracts to properly describe the new division line with respect to the underlying titles. That would not have been a problem in the late 1930s when the ranch was assembled, but after sixty years of heavy machinery clearing out pastures, scraping off rock mounds and bearing trees alike, with fencelines getting rebuilt in new locations after the dozer cleaned the slate, it was more of a challenge.
Fortunately one of the tracts had been surveyed in 1937 by a respected Austin surveying firm whose work was generally first rate and I used their description of the tract to reconstruct where its Southeast corner had been, a corner that had been originally marked in 1922, and with bearing tree accessories. At the time, I saw little else to go on.
Long story short, I relied upon the 1937 respected surveyor's work and gave a tie to a tract corner as reconstructed from it only to discover many years later that the respected surveyor had made a blunder in his calculations that meant that his data was completely unreliable as evidence of the corner. Wider inquiry showed that the corner was actually 10 varas South of where I had set a pipe to mark it on the strength of his work.
Fortunately for me, it was all inside of one 2,400 acre tract and I got to both discover the mistake years later and correct it by setting a marker in the position of the original corner. In a new, improved written description, I did mention the erroneous pipe that, while it wasn't the corner of the tract was now a reference to the new division line corner marked by a brass tablet in concrete. The lessons were these:
1) don't assume that even diligent and reputable surveyors didn't make mistakes and
2) whenever possible, see if you can examine the field book.
paden cash, post: 428673, member: 20 wrote: Only one of the FEMA RMs was recovered at the time and THAT datum disagreed with these USC&G monuments by 1 foot.
A similar situation occurred in a nearby city when the FIRM published an RM elevation for USC&GS M 644 RESET, but the elevation actually went with M 644A, a nearby TBM used by NGS during the reset. M 644A is/was 3.3 feet higher than M 644 reset. I found it when trying to check into another BM, and ended up running a whole lot more levels than I'd budgeted for a measly Elevation Certificate.
I made a mistake once...I thought I was wrong.
Dammit Dave, you beat me to it. I was going to offer it to Kent for him to use.
The RM thing rings a bell. There is a city near here that somehow had an incorrect elevation on the main RM so all the other RM's were off by the same amount. As I recall, that was something like two feet. But, the firm was built from the RM so everything was relative. Just had wrong numbers listed. One foot below flood really was one foot below flood.
More than few jackpots come to mind. Though thankfully most the self-inflicted blunders have been minor &/or easily corrected. The epic stuff usually originated in the engineering side:
-a major super market way too close to the wetlands. We'd got the excond from another firm. They'd located the wet flags with a
I wasn't directly involved, but I remember a situation where a firm loaded points in SPCS, US Feet into an SDR33 set to International feet and staked out pretty much an entire shopping center before they figured out that they had a problem.
Opps pocket post mid story & dont see a delete option on the mobile. Admin; feel free to remove if you like.