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Create Section Corner Position Using Only Accessories

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(@dougie)
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@flga-2-2?ÿ

If the puzzle doesn't fit; you're not using a big enough hammer...

?ÿ

 
Posted : September 8, 2021 11:42 am
(@thebionicman)
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@dougie but it sure can be satisfying to try...

 
Posted : September 8, 2021 11:49 am
(@mark-mayer)
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Posted by: @field-dog

The plan is to RTK each accessory and create a virtual section corner position by using the accessory tie distances. Would you use a distance-distance intersection calculation from the 2 west side accessories? We could use the third distance from the east side accessory as a check.

Given that there are 3 references a least-squares solution is appropriate. Carlson has a function for exactly this problem. If nothing else you can draw 3 circles and select a good average by inspection, or do 3 seperate distance-distance intersections and average the results. If the residuals are small, then you have a truly tight search stakeout. That nail and washer isn't destroyed, it is just covered over. Maybe. If it is destroyed then those reference measurements are the best evidence of its location.

Some PLSs seem to think of references as merely an aid to finding the monument. Others as a means to restore the position. I'm in the latter camp.

Doing CCRs were practically an everyday thing for me in Oklahoma. The law calls for 3 references within 5 chains. Spikes in powers poles and fence posts are very popular for that. That's OK if the pole and or fence post is stable, which they commonly are not. We recently had a thread discussing the suitability of spikes in power poles as TBMs - they were widely panned.?ÿ ?ÿSo I tied those, where found, mostly because they were referenced in earlier CCRs and satisfied the statutory requirement. But I didn't think of them as satisfactory.?ÿ I'd look for better things. Things that could occupied.?ÿ A nail in a culvert headwall is good. Fire Hydrants are pretty good if they have?ÿ clearly identifiable point on them. Sometimes a property corner monument could be found at the right of way line - bonus.?ÿ If necessary I'd set irons, taking care to not place them were they could be mistaken for boundary. Then I'd include a tie to all adjacent PLSS corners that had also been tied. This as well as the state plane coordinate of the corner. All in all I'm comfortable that those corners that I filed on are tied down once and for all.

?ÿ ?ÿ ?ÿ?ÿ

 
Posted : September 8, 2021 11:55 am
(@flga-2-2-2-2-2-2-2-2)
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I'm curious why you don't approach this the proper way (ie: Manual of Instructions) considering OC has CCR's for 99% of the County. What did I miss? ?????ÿ

 
Posted : September 8, 2021 1:50 pm
(@field-dog)
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Posted by: @mark-mayer

That nail and washer isn't destroyed, it is just covered over. Maybe. If it is destroyed then those reference measurements are the best evidence of its location.

A decision to recover the point has not been made yet. In recent years it has become routine for contractors to mill a road before resurfacing it. The point, according to the CCR, falls in the center of the road. We want another crew out there with us. In the meantime, we're trying to recreate the monument by using the accessories. There is a latitude, longitude, scale factor, etc. on the CCR to compare our measurements to.

 
Posted : September 8, 2021 4:48 pm
(@field-dog)
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@flga-2-2?ÿ

You didn't miss anything. I'm not familiar with the Manual of Instructions (BLM?) that you mentioned. Do you happen to have a URL for it?

 
Posted : September 8, 2021 4:54 pm
(@field-dog)
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Posted by: @thebionicman

There is nearly always something reasonable if you plan for it.

I forgot to add this quote with the 2 pictures. It appears that the placement of the 3 nails and discs were well planned.

 
Posted : September 8, 2021 5:13 pm
(@flga-2-2-2-2-2-2-2-2)
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(@bstrand)
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@norm?ÿ

I just dug through a day or two old asphalt to tie a pin about a week ago.?ÿ I figured every surveyor did this.

 
Posted : September 9, 2021 2:28 pm
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