Controlling Intermediate - PowerPoint Presentation

Slide1

Controlling Intermediate

Corners

Instructor:Dennis J. Mouland, PLS

© Witness Tree Consulting, Inc., 2011, All Rights ReservedSlide2

Course Objectives

Define CIC’s for surveying purposesFamiliarize with background of various CIC’s

Discuss evidence analysisReview use and application of CIC’sExamine methods for restoration of lost

CIC’s Slide3

The textbook:

www.blmsurveymanual.org/errataSlide4

Define

What was the normal “level of control” set by the GLO?Section and Quarter-Section CornersThese are controlling, but

intermediate…….Intermediate to the normal level of controlBut still control somethingLine, and most proportioningSlide5

Some CIC’s exist due to procedure

Meander CornersClosing CornersCrossing Closing CornersSubdivisional Corners set previouslySlide6

Others due to field conditions

On-line Witness CornersLine TreesWitness PointsSlide7

How do we know they exist?

They must be in the official GLO/BLM recordAlways in the notesSometimes also shown on the platIf they were noted, you MUST look for themIf found, they MUST be usedSlide8

22.46 A pine, 36ins diam.

ChainsSlide9

LT

WP

1/4

RECORD

MEASURED

Lost 1/4

LT

WP

What CIC’s will do to your surveySlide10

We will discuss some of the CIC’s in detail:Slide11

Meander Corners

Why set to begin with?What is a meander line?Why needed today?If found, how does it control line?Do we use it in proportions of lost corners?

Do we use it to set subdivisional corners?If lost, should it be reset?Slide12

2009 Manual

“A meander corner is established at every point where a standard, township, or section line or special survey boundary intersects the OHWM of a navigable stream or other meanderable body of water.” (3-173)Slide13

MC’sSlide14
Slide15

Meander Corners

Found?Use to re-establish meander line itselfUse to fix alignment at that point of section line

Use to set lost corners on section lineUse to proportion subdivisional corners along section line

Lost?

Must be re-established to determine any riparian issues

If there has been erosion or accretion, the original MC position must be determined AND a new MC set at the current OHWLSlide16

Lost ¼ Corner:

48.13

(R) =

8.10

48.08 (M) X X= 8.09chs

Lost MC:

26.29

(R) =

8.10

26.44 (M) X X= 8.15Slide17

On-line Witness Corners

Why do WC’s exist?What about off-line WC’s?New policy in the 2009 Manual which aligns with BLM internal policyAlways controls the alignment

Use differs between section corners and quarter section cornersSlide18

True Story

WC

Sec. Cor.

¼ Cor.

Private Land

National ForestSlide19

Where Witness Corners might be a good idea!Slide20

WC 5.00

40.00

40.00

1/4

WC

WC

Record

Measured

Result

34.62

45.22

34.62

5.024

40.196

WC 1/4Slide21

WC Section Corner

40.00

40.00

Record

40.00

40.00

WC 5.00

Result

40.00

40.00

40.00

40.00

WC

Controlling bearing pushed through at 5.00 chains (Record)

Brg

Brk

at Sec

Cor

Slide22

Line Trees

Must be called for in the notes, and cite species, diameter, and distance to the nearest link.Courts have ruled that they are monuments of the original survey, which causes an angle point in the line.Used for proportioning lost corners and subdivisional corners. See

BLM 6-28.Slide23

40.00

7.54

1/4

Record

LT 32.46

¼ LOST

Measured

S1/16 to be set

Proportion for 1/4

M= 47.45

M=32.40

47.54

=

7.54

47.45 X

32.46

20.00

32.40 XSlide24

Witness Points

How differ from Witness Corners?Sometimes referred to as “artificial line trees”Utilized the same as line treesControl line and alignment for lost corners and subdivisional cornersSlide25

Closing Corners(2009—7-45)

When an original closing corner is recovered off the line closed upon and the new monument is established at the true point of intersection, the

original position will control in the proportionate restoration of lost corners dependent upon the closing corner. In a like manner the positioning of sixteenth-section corner(s) or lot corner(s) on the closing line, between the quarter-section corner and the closing corner, will be based on the measurement to the

original

position of the closing corner.Slide26

CC

CC

CC

1.21

1.21

2.06

1/4

Lost 1/4

1/4

N1/16ths to be set

True section corners at intersection points

Proportions go to

original

CC positions

Actual

S

ection Corner

Lost/sub

cors

proportioned to

orig

pointSlide27

CC

Sec

Cor

¼ Cor.

¼ Cor.

1/16

th

to be set

R=40.27

M=40.22

Fd

. 0.28 links north of twp. line

40.27

=

20.27

40.22 X X=20.24

MINUS 0.28 = 19.96

40.27

=

20.00

40.22 X

X=19.975Slide28

Crossing Closing Corners

Closing corners in some cases have been established where a line of the survey crosses previously surveyed claim lines (section 3-74 “Intersecting and Terminating Section Lines”). These corners are established after a retracement of the line intersected and

monumented when administratively required. In the past, these corners have been termed “crossing closing corners.” (2009—7-48)Slide29
Slide30
Slide31

CCC’s

Will bend lines if it controls the line when createdCan be used to proportion lost corners if it controls:Non-rectangular cornersSubdivisional cornersLost PLSS cornersSlide32

When you find a CIC………

Remonument as an APTake accessoriesMake the details part of your recordWhere on the line trees?Slide33

If they are lost………

Was it ever retraced and shown off-line?Re-establish by proper method (7-34)Never used by a survey?May not need to be re-set

MC’s always should be re-setCCC’s usually should be re-set – B/B intersectWP still needed?CC’s adjusted once: then treated as equal

Rec. MeasuredSlide34

Remon

as an AP

Take accessoriesSlide35

Conclusion

CIC’s exist in the fieldYou must search the record for their existenceYou must search for them in the fieldYou must use them as appropriate control for the line as is, lost corners, or subdivisional corners to be set

Their use is not optionalThey will change your survey resultsSlide36

CONTROLLING INTERMEDIATE CORNERS

© Witness Tree Consulting, Inc., 2011, All Rights

Reserved