I am retracing a Survey by our Department.
The work was done in 1978 and 1979 and the Record of Survey was filed in 1980.
I used GPS to get a geodetic bearing on my work and missed his bearings by about 1'. So I get out his field notes and calculations and see that he did three altitude solars (of several pointings each). He wrote all times are standard time in the notes. My first suspicion was it is really daylight time because the date of the solar was 07-14-1978. But then going through it I found the mistake. Two are OK but the first has a blunder of 1' in the declination. He meaned the three results and round to a nearest minute bearing.
I recalculated his solars and rounded them to a nearest minute bearing and now I am within 3" of that, pretty good. I had to take his word for it on the almanac data (the blunder was after converting midnight declination to observation time, he just wrote it down wrong when transferring the number down).
I checked his almanac data against ICE here at home which is an old DOS almanac program I downloaded from somewhere. His raw almanac numbers are good.
I see the same progression in the bearings that I have seen in my work when I tried to do an altitude solar.
:stakeout: :good:
So what's the point?
If you think that the corner is whereever the surveyor set it - mistake or no mistake - then why worry about the basis of bearing?
So what's the point? Change
When it comes to reissueing work that will have different bearings, distances or references it is good to include the reason for the changes and to reference the prior and recent.
It does not sound like Dave is disputing any corner, he just may or may not change the reference.
Errors can occur in any work, but in well doumented work it is easier for subsequent surveyors to find and correct said errors and still maintain the record.
It would be interesting to see how concisely Dave references said change if he issues a change at all.
At the time of the prior observation simple clock error could have caused greater difference. In my opinion Dave was rather pleased with the previous work and glad he had the notes to figure it out.
Paul in PA
I don't think the mistake would even cause a burp with the surveyor. The altitude method and using a dec sheet for the day, you were happy if your bearing was within a minute! Accurate time wasn't of any concern due to the method and strength of the spherical trig.
Pablo B-)
Is there some problem?
?
Is there some problem?
From reading the thread I would guess that he found a "Mistake in [an] old solar calculation...", but I could be wrong. 😛
