Witness Monuments

To know there is a witness monument demands there be a map in hand at a pre-calculated location based on existing coordinates.  The map will simply show a measurement on-line at a whole-foot number.  The wording that suffices normally is southerly or south-south westerly as you merely need a "close enough" direction to begin your search.  The basis of bearings may be different from the original basis of bearings.  From two-feet to well over 100 feet are typical witness distances.  Saw distances of 85 and 150 feet on a survey this past week of a survey where a corner fell at the intersection of the centerlines of a river and a named creek.

Reference monuments are an entirely different story.  They may fall in any direction from the monument they are referencing and at any distance.  They may be near or below surface level to more than head high in some cases.  They may be sloped distances using a steel tape or they may be horizontals distances only determined by our black boxes.

My experience with witness points is that they were always individual natural points like trees or rocks or old fence posts with a compass bearing and distance to tenths to the true point. They were meant to be used to recover the true point that had previously been set.

My definition of a reference point is something that has been set with a bearing and distance to a true point that cannot be actually set like in a river. I have set several and they are always on the lot line with a distance to the true point. A simple example of a reference point that all of us have set are L+D's in the sidewalk on an offset to the PL corner and on the lot line bearing.

The following is taken from the current Kansas Minimum Standards and uses witness and reference interchangeably.

"In such cases where the placement of a required monument at its proper location is impractical, it shall be permissible to set a reference or witness monument close by the point, and if such reference monument is set, its location shall be properly shown on the survey plat. When conditions warrant setting a reference or witness monument on an offset, the location shall be selected so the reference monument lies on a line of the survey or on the prolongation of such line. Reference or witness monuments shall not be offset in fractional feet or less than two feet from the true corner unless a physical obstruction affects their location"

The BLM makes the distinction that a Witness Monument is 'on- line' either short or long (on a prolongation) of the subject corner. The BLM calls them a "Witness Corner". A reference mon is offset in any direction at a stable location.

It will require more Reference Monuments (preferably 4) to accurately (reasonably) intersect a corner than a single Witness Corner. IMHO. 

It has always been my understanding that a cap stamped as a witness corner is on the line. A cap stamped as a reference monument is not on the line. 

Well it looks like I have my labels reversed. Thanks for the references guys.

That’s pretty much how I learned it too - witness monuments/corners are usually kept on line or on a prolongation, while reference monuments can be offset pretty much wherever conditions make sense. I’d definitely use the full bearing and distance in the notes though, even if the plat just shows a simple northerly/southerly callout. Makes recovery a lot less ambiguous later on.

And technically, a witness corner isn't necessarily "on-line". A witness corner 100' south of the E1/4 of a Section creates an angle point in the section line from the SE corner to the WC, then instead of extending the line 100' the 1/4 is online to the NE corner and 100'. I suppose that same situation can be created in subdivisions and tracts. I will say I've never worried about it much, normally I will extend the line. 

Posted by: @mightymoe

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And technically, a witness corner isn't necessarily "on-line". A witness corner 100' south of the E1/4 of a Section creates an angle point in the section line from the SE corner to the WC, then instead of extending the line 100' the 1/4 is online to the NE corner and 100'.

That doesn't make any sense, imo, that you would put the witness corner on the opposite side of a section line (NE corner to E 1/4) you're apparently measuring.  At that point it would become a reference monument.  If I had some weird situation like that where I had to put the monument on the opposite side I would go tie the SE corner and put it 100' south of the E1/4 on that line instead.

@bstrand 

Exaggerated sketch:

The kink happens at the WC set from the south. Then line is held to the next monument to the north instead of extending line and kinking it at that position. 

@mightymoe I guess I don't understand why it's being put on the opposite side of the monument.  Put it on the line either between the north section corner and the 1/4 or the south section corner and the 1/4, imo.  I would say the way you have it there is a reference monument not a witness corner.

@bstrand 

I'm not being clear I guess. My example is retracing original monuments. The WC isn't being set, it's being recovered from original notes and the plat. If you're setting the monuments that's different. For a witness corner set during the original survey the line kinks at the WC. And it's a different process for a section corner since there are four directions to consider. 

Posted by: @mightymoe

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My example is retracing original monuments. The WC isn't being set, it's being recovered from original notes and the plat.

Oh.

Posted by: @mightymoe

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For a witness corner set during the original survey the line kinks at the WC.

That doesn't make any sense to me either.  Why wouldn't you measure up the line, calc or reset the 1/4 corner, and continue working from that?

@bstrand 

It's like a line tree, the point being the line is run, for some reason the corner can't be set, maybe it's in a creek, the line is run to the witness corner, then it's continued to the next section corner which is set, instead of projecting the line for the 1/4 the witness corner monument is held for line and the 1/4 falls between the witness corner and the next monument. It's explained in the Manual, can't say off the top of my head where, but whenever I do have an original WC to deal with I usually hunt down the relevant chapter. 

Usually when I see reference monuments or RMs, they're random, more like formal control points for which DOT or whoever has published the coordinates on so other surveyors can quickly get onto project centerlines or points on a ROW or something like that. Usually they get set somewhere safe to occupy so surveyors don't have to get in the traveled way to tie centerline mons. Lot of times it's not practical to set monuments on the ROW limits due to the terrain. Most of the witness corners, WCs, are on line with an extension to reference the corner that couldn't be set due to circumstances. On the GLO/BLM surveys, they're often WCMC, or a witness to a meander corner, which with the official notes, you would use to recreate the record meanders. Those are typically set online and set far enough back from a bank or shoreline that they're not going to get wiped out by erosion. So I think of the two as being very different. 

This is the section discussing WC's in the 2009 Manual. 

As can be seen line a line tree the WC becomes an angle point, assuming the text can read here, it's page 152. 

The BLM is moving away from WC's towards RM's. However, in the real world of tracts and lots it's important to think of how a monument will be used. 

I've had much better results setting a WC on line between owners than an RM, the monument gets seen and fenced to if you're not extremely careful. A WC on the ROW 2' from a corner that's occupied by a big post in concrete will get fenced to and now the fence is 2' into one of the neighbors. Better to set the WC 2' up the line and have the ROW fence be off and the property fence be on line. In those situations RM's are normally difficult for the landowners to use. 

Posted by: @mightymoe

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I've had much better results setting a WC on line between owners than an RM, the monument gets seen and fenced to if you're not extremely careful. A WC on the ROW 2' from a corner that's occupied by a big post in concrete will get fenced to and now the fence is 2' into one of the neighbors. Better to set the WC 2' up the line and have the ROW fence be off and the property fence be on line. In those situations RM's are normally difficult for the landowners to use. 

I had a coworker run into something like this.  Corner landed in an irrigation box so he set a witness.  An adjoiner built a long, expensive fence to the witness corner, found out afterwards that it was wrong and the sued my coworker.  Judge ruled it wasn't my coworker's fault the adjoiner didn't or couldn't read the survey correctly.

@bstrand 

You always want to think about how things get messed up. I learned the same way, put in a 2' WC on the street side and it got used as line between the neighbors, even had a post up telling that it was off line. There was no way to set the corner.