The BLM/GLO manual of 1973 has a series of examples of corner markings/other information that seem to be nearly identical to the examples in the 1930 manual, except the dates have been changed. The dates have been "modernized" to 1971 or 1972.?ÿ In some cases, it doesn't make sense. We were not using chains in 1972 to make measurements. It just seems odd. Curious if someone can shed some light on this?
Examples:?ÿ (page numbers from GLO manual, not pdf)
1930?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ ?ÿ?ÿ 1973
Page Date ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ ?ÿ ?ÿPage Date
--------------------------------------
234?ÿ?ÿ 1916 -->?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ 109?ÿ?ÿ 1971
356?ÿ?ÿ 1927 -->?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ 184?ÿ?ÿ 1971
471?ÿ?ÿ?ÿ1927?ÿ -->?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ?ÿ 242?ÿ?ÿ 1972
https://www.ntc.blm.gov/krc/uploads/538/1930%20Manual.pdf
https://www.ntc.blm.gov/krc/uploads/538/Manual_of_instructions_1973.pdf
What are you confused about? For the most part the markings are the same in the 2009 manual?ÿ too. BLM doesnt measure with chains, but in most religions they still measure in chains today.
Chains haven't been used to do the measuring for quite some time but chains are still the official unit of length for BLM surveys today. So the examples are just as relevant as ever.?ÿ
Yep, the BLM still uses chains for their units, even for dependent resurveys of mineral surveys (a little odd for me to see lots of distances reported as 4.545 and 22.272 chs).?ÿ The only thing that has changed between 1930 and 2009 is that they report distances today to 0.001 chains (0.1 links) rather than 0.01 chains (1 link).
Thank you all. I shouldn't have put the chain comment in there, as it distracted from my original question. My question is for the same example, why was the date changed??ÿ See these images. This has been done throughout.
?ÿ
(should say page 236 instead of 234 on first post, but can't figure out how to edit the first one. The edit symbol shows up for this post, but not the first one)
The date was changed because someone doing a survey under the 1973 manual would not be stamping a monument in 1916. I suppose the 1930 manual just used diagrams from an older manual without changing them. The 2009 manual updated the dates again. It doesn't really matter, the point is just to show where the year goes on the cap.
Many BLM offices still report to the nearest link. Some use feet to the nearest 0.1'.?ÿ
The explanation paragraph doesn't mention what the bottom number is for.?ÿ So, an editor in 1971 might have asked "what does the 1916 stand for?".?ÿ That far removed from the actual date of publication, it wouldn't be readily apparent that the number represents a date.?ÿ
It's critically important to note,,,,,,all examples are devoid of dimples.?ÿ
Yeah, but aren't those examples of how to prepare the disk before putting it on a rod? You don't put the dimple in until it's in place and you've measured to the last McMillimeter where it goes.
I stamp the cap complete with dimple then go set it. I can get it within the error ellipse of the control point so I don't see the point in setting the dimple off center. It's just a mark to reduce centering errors for measurement purposes. Usually the monument itself is of sufficient practical precision for the purpose to which it was set.
We stamp the caps just like the latest manual instructs us too. Nothing is added or left out except the PLS#.?ÿ
I hope they come out with a new manual, our dates are 10 years off now.?ÿ
I set my monuments at the corner. The marks on the cap are just to identify it...
I can see your perspective(s) now. The way I read it was that it was an older survey that was given a new date.?ÿ My preference would have been to keep the original date when the example was written. Or give an example of a new survey with a current date.?ÿ
I also didn't realize BLM surveys were still reported in chains. Thanks!
p.s. And if anyone who is reading this chain (no pun intended) has a copy of the article written by Larry Young (1986) about the transcription of the GLO field notes by the ladies of WPA,?ÿ would appreciate a copy.
Well I suppose you could look at as if the 1916 survey was resurveyed in 1930, 1973, and 2008. Resurveys and original surveys are identically marked.
There was another Manual between 1930 and 1973. The 1947 was in use until the 1973 version.