What is the relative precision (accuracy ratio) in a metes and bounds survey?

Chapter Title:

Foundations of Legal Descriptions: Metes and Bounds

Introduction:

Chapter 2: Foundations of Legal Descriptions: Metes and Bounds

Introduction

The precise and unambiguous delimitation of real property is fundamental to land ownership, transfer, and resource management. Among the methodologies employed to achieve this, the metes and bounds system stands as a cornerstone, particularly in regions predating standardized land surveying practices. This chapter provides a detailed exploration of the metes and bounds system, elucidating its scientific underpinnings and practical applications.

The metes and bounds system is a method of land description that delineates property boundaries through a sequential articulation of distances (metes) and directional bearings (bounds) originating from a known reference point. Its scientific importance lies in its reliance on geometric principles and angular measurements to define a closed polygon representing the parcel's perimeter. The accuracy of a metes and bounds description hinges on the precision of surveying techniques, angular resolution, and the stability and unambiguous identification of reference points. The system’s flexibility allows for the description of irregularly shaped parcels that deviate from orthogonal grid patterns, making it crucial in areas with complex topography or historical land divisions. The system provides directions and distances that could be followed by a surveyor to trace the boundaries of the property.

This chapter aims to equip students with a comprehensive understanding of the metes and bounds system. Upon completion of this chapter, students will be able to:

1. Define the fundamental elements of a metes and bounds description, including reference points (monuments), courses, and distances.
2. Interpret directional bearings expressed in degrees, minutes, and seconds relative to cardinal directions.
3. Understand the significance of the Point of Beginning (POB) and True Point of Beginning (TPOB) in establishing the locus of a property description.
4. Analyze and interpret typical "calls" or instructions within a metes and bounds description.
5. Discuss the application of modern surveying technologies, such as laser transits and satellite-based positioning systems, in enhancing the accuracy and reliability of metes and bounds surveys.
6. Recognize the limitations and potential sources of error associated with metes and bounds descriptions and understand the importance of independent verification.

By mastering the principles of the metes and bounds system, students will gain a critical foundation for interpreting legal descriptions, assessing property boundaries, and contributing to informed decisions in real estate appraisal, land development, and related fields.

Topic:

Foundations of Legal Descriptions: Metes and Bounds

Body:

Chapter 4: Foundations of Legal Descriptions: Metes and Bounds

II. Metes and Bounds System

The metes and bounds system is the oldest and often most intricate method of legally describing property. It defines a property's boundaries by specifying their metes (distances and directions) and bounds (landmarks or monuments) relative to a known starting point. This method essentially provides a set of instructions that a surveyor could follow to trace the exact perimeter of the land parcel. While seemingly simple in concept, the application relies on principles of surveying, geometry, and a thorough understanding of spatial relationships.

The accuracy and reliability of a metes and bounds description are directly linked to the precision of the measurements and the permanence of the referenced landmarks. The evolution of surveying equipment, from chains and compasses to laser transits and GPS technology, has significantly impacted the precision achievable in metes and bounds descriptions.

There are three basic elements in a metes and bounds description:
1. Reference Points
2. Courses, and
3. Distances.

A. REFERENCE POINTS

A reference point, often called a monument, is a readily identifiable, fixed location used as a basis for taking measurements. It provides a link between the property being described and the surrounding environment. The monument can be natural (e.g., a large rock, a specific tree) or artificial (e.g., a survey marker, a metal stake).

All metes and bounds descriptions originate at a reference point that correlates to adjoining surveys. This initial reference point is known as the POINT OF BEGINNING (POB). Bounds describe the point of beginning, which is also the point (or reference point) of return, and all intermediate points.
In some cases, the POB might be offset from the actual starting point of the property boundary description. When this happens, the point at which the description of the actual property boundaries begins is called the TRUE POINT OF BEGINNING.

B. COURSES AND DISTANCES

Once the true point of beginning is established, the metes and bounds description proceeds to describe each boundary of the property.

Metes refer to the direction from one reference point to another and the distances between those points. Courses are angles in degrees, minutes, and seconds from north or south. The boundaries are described in sequential order, ending back at the True Point of Beginning.

Think of a metes and bounds description as a set of instructions allowing someone to “walk” the property's perimeter. Each instruction, called a “call,” dictates the direction (course) to follow along a boundary and the distance to travel before changing direction.

1. Angular Measurement:

Understanding angular measurement is crucial for interpreting courses. A circle is divided into 360 degrees (°). Each degree is further divided into 60 minutes ('), and each minute into 60 seconds ("). Therefore:

• 1 degree (1°) = 60 minutes (60')
• 1 minute (1') = 60 seconds (60")
• 1 degree (1°) = 3600 seconds (3600")

Formula: Convert decimal degrees to degrees, minutes, seconds (DMS)
* DMS = Degrees + (Minutes/60) + (Seconds/3600)

Example: Convert 30.263889° to DMS

• Degrees = 30°
• Minutes = 0.263889 * 60 = 15.83334 (round to 15')
• Seconds = 0.83334 * 60 = 50 (round to 50")
• DMS = 30° 15' 50"

2. Bearing Conventions:

A course is defined by its bearing, which specifies its direction relative to either North or South. There are two primary ways to express a bearing:

• Cardinal Directions: If a course runs precisely along one of the cardinal directions (North, South, East, or West), it is simply stated as such.
• Quadrant Bearings: Courses that do not align with a cardinal direction are expressed using a quadrant bearing. This system specifies the angle of the course relative to either North or South within one of the four quadrants (Northeast, Northwest, Southeast, Southwest).

Northwesterly and northeasterly courses are stated in terms of the angle from north; southwesterly and southeasterly courses are stated in terms of the angle from south. The angle is given in terms of degrees, minutes, and seconds. (In angular measurements, a degree (º) is equal to 1/360th of a full circle; a minute (‘) is equal to 1/60th of a degree; and a second (“) is equal to 1/60th of a minute or 1/360th of a degree.) The size of the angle is written in between the two cardinal directions that form the boundaries of the quadrant.

Example: A southeasterly course that forms an angle of 89º 19’ E degrees from true south would be stated as South 89 degrees 19 minutes East, or S 89º 19’ E. The angle is written between the two cardinal directions that identify the quadrant.

3. Example Call:

A typical "call" might read: "South 89 degrees 19 minutes East, 2664 feet". This means:
* Start from the current point.
* Turn to a direction that is 89° 19' East of South.
* Travel in that direction for a distance of 2664 feet.

C. CLOSURE AND ERROR OF CLOSURE

A fundamental principle of metes and bounds descriptions is closure. A mathematically sound description should, when traversed, return precisely to the True Point of Beginning. However, due to measurement inaccuracies, imperfect instruments, and human error, perfect closure is rarely achieved in practice.

1. Error of Closure:

The error of closure is the distance between the point where the survey actually ends and the True Point of Beginning. It represents the accumulated error in the survey measurements.

2. Relative Precision:

The relative precision (also known as the accuracy ratio) is a measure of the quality of the survey. It is expressed as a ratio comparing the error of closure to the total perimeter of the surveyed area:

Relative Precision = Error of Closure / Perimeter

Example:

Suppose a survey has a perimeter of 5000 feet and an error of closure of 0.5 feet. The relative precision would be:

Relative Precision = 0.5 feet / 5000 feet = 1 / 10,000

This means that for every 10,000 feet measured, there is an error of 1 foot. Generally, a relative precision of 1/10,000 or better is considered acceptable for urban surveys, while 1/5,000 might be acceptable for rural surveys.

D. PRACTICAL APPLICATIONS AND EXPERIMENTS

1. Traverse Calculation:

A traverse is a series of connected lines whose lengths and directions have been determined. Traverse calculations involve using trigonometry (specifically sine and cosine functions) to break down each course into its North/South and East/West components. These components can then be summed to determine the overall displacement from the starting point.

Steps:

1. Convert bearings to azimuths: Azimuths are angles measured clockwise from North, ranging from 0° to 360°. This provides a consistent reference frame for calculations.

2. Calculate latitudes and departures:

   • Latitude (North/South component) = Distance * cos(Azimuth)
   • Departure (East/West component) = Distance * sin(Azimuth)

   Note: Remember to adjust for quadrant when interpreting sine and cosine results.
   3. Sum latitudes and departures: Add up all the latitudes and all the departures. In a perfect survey with mathematical closure, the sum of latitudes should be zero, and the sum of departures should also be zero.

3. Calculate error of closure:

   • Error in Latitude = Sum of Latitudes
   • Error in Departure = Sum of Departures
   • Linear Error of Closure = √( (Error in Latitude)^2 + (Error in Departure)^2 )

2. Using Area Calculation Software:

Surveying software and online tools can automate area calculations from metes and bounds descriptions. These tools typically require you to input the courses and distances in a specific format. The software then uses coordinate geometry to compute the area enclosed by the boundary. Many such tools can also check for closure and identify potential errors in the description.

3. Impact of Monument Degradation/Relocation:

Over time, monuments can be damaged, moved, or even lost. The impact of such changes on property boundaries can be significant and often leads to disputes. An exercise could involve examining old surveys and simulating the effect of shifting a key monument by a small distance. This demonstrates how seemingly minor discrepancies can affect the overall boundary and potentially encroach on neighboring properties.

E. METES AND BOUNDS DESCRIPTIONS IN APPRAISALS

Metes and bounds descriptions can be very long and complex, which creates opportunities for errors whenever the description must be copied. For this reason, the description is often photocopied from a deed or other document, and the photocopy is attached as an addendum to the appraisal. This does not guarantee the accuracy of the description, but it at least prevents errors in its transcription. Appraisers can calculate a parcel area imputing the metes and bounds description into a computer program. The computer program can also simulate a survey around the boundary of the property to see if the description ends at exactly the point of beginning.

The laser transit used by surveyors has made for more accurate determinations of points, directions, and distances. Uncertainty with regards to points of beginning has largely been eliminated through the use of established BENCH MARKS, which are survey markers set in heavy concrete monuments. Satellite technology has also been utilized by surveyors to locate points.

The metes and bounds system is often used instead of the rectangular survey system, and is especially good when describing unusual or odd-shaped parcels of land.

F. CONCLUSION

The metes and bounds system, while complex, forms a cornerstone of property law. Understanding its fundamental principles, including reference points, courses, distances, and closure, is crucial for anyone involved in real estate, surveying, or legal professions. The evolution of surveying technology has enhanced the accuracy and reliability of metes and bounds descriptions.

ملخص:

Foundations of Legal Descriptions: Metes and Bounds

This chapter focuses on the metes and bounds system, the oldest of the three primary legal description methods used in the United States. The core scientific principle behind metes and bounds is the accurate and unambiguous definition of property boundaries through a series of measured directions (courses) and distances from established reference points. Unlike informal descriptions (e.g., street addresses), legal descriptions, including metes and bounds, are essential for precisely identifying a property's exact boundaries, which is a critical component of real estate transactions and appraisals.

The fundamental elements of a metes and bounds description are:

1. Reference Points (Monuments): These are fixed, identifiable locations serving as the foundation for all measurements. Reference points can be natural (e.g., trees, rocks) or artificial (e.g., survey markers, metal stakes), with the Point of Beginning (POB) being the initial reference point to locate the property within the surrounding area. The True Point of Beginning indicates where the description of the actual property boundaries begins.
2. Courses: Courses specify the direction of a boundary line, expressed as angles (degrees, minutes, and seconds) relative to either north or south. Accurate angular measurement is crucial for defining the path of each boundary segment.
3. Distances: Distances represent the length of each boundary line segment between reference points. Precise distance measurement is essential for determining the size and shape of the property.

A metes and bounds description creates a set of instructions that, when followed by a surveyor, traces the perimeter of the property, returning to the true point of beginning. The accuracy of metes and bounds descriptions has improved with laser transits, GPS, and established benchmarks (survey markers set in concrete monuments), ensuring more accurate determinations of points, directions, and distances.

The metes and bounds system is particularly useful for describing irregularly shaped parcels where the rectangular survey system may not be applicable.

Implications for appraisers include the need to recognize whether a description meets local standards. Appraisers can utilize computer programs to calculate parcel areas and simulate surveys to verify the closure of the description (ensuring it returns to the POB), and to detect potential errors in the description. While it is not typically the appraiser's responsibility to create or survey the legal description, understanding the principles of metes and bounds is crucial for interpreting and using these descriptions effectively.