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Double Proportion Problem

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slim
 slim
(@slim)
FNG Member
Problem4

I'm working on this double proportion problem I found in American Surveyor magazine and I'm getting the correct easting but my northing is the incorrect. I'm not in a PLSS state so I rarely work with sections, but I am preparing for both the PS and PLS exams so any clarification on what I'm doing wrong will be very helpful. I'm getting C but the correct answer is A. Thanks.

Here is a link to the actual page if the image doesn't come through clearly: (Question 4)

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Topic starter Posted : June 17, 2020 4:07 am
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Charles L. Dowdell
(@charles-l-dowdell)
500+ posts Member

Need a better picture. This one is too blurry to read the cornnuts. I tried everything in my photo programs to make a decent picture, but it would not clear up so that it is readable.

.

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Posted : June 17, 2020 4:30 pm
aliquot
(@aliquot)
1,000+ posts Member

Something is missing from that question. Do you know what it is?

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Posted : June 17, 2020 4:43 pm

aliquot
(@aliquot)
1,000+ posts Member

Looking at the other questions there are other problems too. I can assure you NCEES does a better job writing questions than this. 

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Posted : June 17, 2020 4:49 pm
Charles L. Dowdell
(@charles-l-dowdell)
500+ posts Member

This is not a Double Proportion corner since it is a ¼ corner and not a section corner and is a Single Proportion for reestablishment. I come up with C as the cornnuts  for the ¼ corner to Sections 9 and 16.

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Posted : June 17, 2020 9:05 pm
Dave Karoly
(@dave-karoly)
10,000+ posts Member

@charles-l-dowdell

wouldn't you dp the section corner then sp the quarter section corner?

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Posted : June 17, 2020 9:11 pm

Dave Karoly
(@dave-karoly)
10,000+ posts Member

Assuming the north-south section line is cardinal North and 80 chains plus 40 chains (GLO record) AND the east-west section line is cardinal east with given distances in chains (GLO record) I get answer A.

coordinates at the corner common to 8/9/16/17 are N19,926.667; E7,603.609.

 

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Posted : June 17, 2020 9:28 pm
Charles L. Dowdell
(@charles-l-dowdell)
500+ posts Member

@dave-karoly I got to thinking about this and I should have proportioned in the section corner first and then single proportioned in the ¼ corner. Must be a sign Old Age is creeping up on me.

This post was modified 1 year ago by Charles L. Dowdell
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Posted : June 17, 2020 10:24 pm
Charles L. Dowdell
(@charles-l-dowdell)
500+ posts Member

@dave-karoly  You didn't complete the problem. It asks for the ¼ corner to Sectipns 9 & 16. I get the same cornuts as you for the section corner. I'll redo  my single proportion for the ¼ corner tomorrow.

This post was modified 1 year ago by Charles L. Dowdell
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Posted : June 17, 2020 10:54 pm

slim
 slim
(@slim)
FNG Member

@charles-l-dowdell Thanks, I wasn't doing that but using this method gets me the correct answer!

Quick breakdown:

Northing of section corner 8,9,16 & 17 is 19926.67 so:

19926.67+(40.05/80.10)(19800.00-19926.67)=19,863.335

I was right there the entire time, I was caught up on using only the given original monuments.

Hopefully like one of the others suggested, if a problem like this is to come up for me on my exam its worded a little different and asking for just the section corner.

 

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Topic starter Posted : June 18, 2020 3:50 am
slim
 slim
(@slim)
FNG Member

@aliquot Thanks for the reassurance, I really hope so. I'm just trying to do any questions I can find so I'm prepared for any senerio given to me.

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Topic starter Posted : June 18, 2020 3:56 am
Allen Wrench
(@allen-wrench)
200+ posts Member

I computed the answer in red.  I screwed up the first time and put all the corners on the east-west line in-line with the existing corners.  But that line will deflect at the double-proportioned section corner.  I'm guessing that's the the original poster in this thread got the easting correct, but the northing wrong.  Two steps - 2P the section corner, then 1P the quarter corner on that new line.

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Posted : June 18, 2020 5:23 am

Dave Karoly
(@dave-karoly)
10,000+ posts Member

@charles-l-dowdell

my post last night is confusing, it was late.

i did calculate my way to answer A but it's confusing how I posted the coordinates for the section corner at the end like that.

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Posted : June 18, 2020 5:49 am
Dave Karoly
(@dave-karoly)
10,000+ posts Member

My calculation:

image
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Posted : June 18, 2020 6:43 am
MightyMoe
(@mightymoe)
5,000+ posts Member

No bearings, no chains, no notes, no answer. I suppose you can "assume" all the elements that go into a calculation, but even for the N1/4 of Section 16 it's critical that you know at least if the north line of 16 is an even or odd chain length. That will effect the 1/4 location.

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Posted : June 18, 2020 6:45 am

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