What You Will Learn


1. Introduction: What is the Area by Coordinates Formula?

The Area by Coordinates Formula is a mathematical method used to calculate the area of a polygon when the coordinates of its vertices are known.

You can use:

It is the fastest and most reliable method for calculating the area of:

This formula is widely known in surveying as the Coordinate Method, and is used in total station processing, GIS software, CAD programs, and online calculators.


2. The Formula: Area by Coordinates (Shoelace Formula)

Let a polygon have n vertices with coordinates: (x1,y1),(x2,y2),…,(xn,yn)(x_1, y_1), (x_2, y_2), …, (x_n, y_n)(x1​,y1​),(x2​,y2​),…,(xn​,yn​)

The area AAA is: A=12∣∑i=1n−1(xiyi+1−yixi+1)+(xny1−ynx1)∣A = \frac{1}{2} \left| \sum_{i=1}^{n-1}(x_i y_{i+1} – y_i x_{i+1}) + (x_n y_1 – y_n x_1) \right|A=21​​i=1∑n−1​(xi​yi+1​−yi​xi+1​)+(xn​y1​−yn​x1​)​

🔍 Simple Explanation

  1. Multiply each x-coordinate by the next y-coordinate
  2. Multiply each y-coordinate by the next x-coordinate
  3. Subtract the two sums
  4. Divide by 2
  5. Take the absolute value

This method works for any polygon, including irregular shapes.


3. Why Surveyors Use the Area by Coordinates Formula

Surveyors love this formula because:

✔ Very accurate

It works perfectly for both small and large areas.

✔ Works with any shape

Straight boundaries, irregular parcels, concave shapes — no problem.

✔ Easy to automate

Total stations, GPS devices, GIS systems, and calculators all use this internally.

✔ Fast

Even a 20-point polygon can be calculated in seconds.

✔ Compatible with all coordinate systems

As long as coordinates are in meters, the result is in square meters.


4. Step-by-Step Example (Most Helpful for Users & SEO)

Consider a land parcel with the following coordinates:

PointX (Easting)Y (Northing)
1100200
2140250
3180220
4130180

Step 1: Multiply xᵢ by yᵢ₊₁

Sum A = 25,000 + 30,800 + 32,400 + 26,000 = 114,200

Step 2: Multiply yᵢ by xᵢ₊₁

Sum B = 28,000 + 45,000 + 28,600 + 18,000 = 119,600

Step 3: Subtract

114,200−119,600=−5,400114,200 – 119,600 = -5,400114,200−119,600=−5,400

Step 4: Take absolute value

∣−5,400∣=5,400| -5,400 | = 5,400∣−5,400∣=5,400

Step 5: Divide by 2

Area=5,4002=2,700 sq. meters\text{Area} = \frac{5,400}{2} = 2,700 \text{ sq. meters}Area=25,400​=2,700 sq. meters

✔ Final Area = 2,700 m²

You can convert this:


5. Area Conversion Table (Helpful for SEO & Surveyors)

UnitConversion
1 sq meter10.7639 sq ft
1 hectare10,000 sq m
1 acre4,046.856 sq m
1 sq km1,000,000 sq m

6. How to Use the Formula for Latitude/Longitude

You cannot directly apply the formula using degrees.

You must first convert:

Then apply the area formula in meters.

This is why most online calculators automatically convert geodetic coordinates to planar coordinates.


7. Using the Area by Coordinates Formula in Different Fields

⭐ Surveying

Used to calculate land boundaries and plot areas.

⭐ Civil Engineering

Used in earthwork, site layout, and planning.

⭐ Agriculture

Farmers measure field areas for irrigation, pesticide planning, yield estimation.

⭐ GIS

Used for calculating polygon areas in spatial analysis.

⭐ Drone Mapping

Photogrammetry software uses polygon coordinates to compute field areas.


8. Common Mistakes When Using Area by Coordinates Formula

❌ Wrong point order

Points must be in:

Random order gives wrong results.

❌ Not closing the polygon

The last point is NOT repeated — the formula closes automatically.

❌ Using lat/long without converting

Degrees will give meaningless area values.

❌ Mixing units

Meters with feet causes major errors.

❌ Using concave shapes incorrectly

The formula works for concave polygons, but self-intersecting (bow-tie) shapes fail.


9. Why Online Area by Coordinate Calculators Are Popular

People search for Area by Coordinates Calculator because:

✔ It saves time

Manual calculation is slow for large datasets.

✔ Accuracy

Avoids human multiplication errors.

✔ Supports many coordinate formats

UTM, lat/long, site grid, CSV files.

✔ Useful for fieldwork

Surveyors use mobile calculators during site visits.


10. Complete SEO-Friendly FAQ Section

Below is a powerful FAQ block designed to boost ranking.


FAQ 1: What is the Area by Coordinates Formula?

It is a mathematical formula (Shoelace Formula) used to calculate the area of any polygon using its coordinates (x, y).


FAQ 2: Can I calculate area from latitude and longitude?

Yes, but only after converting lat/long to UTM or another projected coordinate system.


FAQ 3: Does point order matter?

Yes. Points must be arranged clockwise or counter-clockwise. Random order produces incorrect results.


FAQ 4: What units will the area be in?

If coordinates are in:


FAQ 5: Is the Area by Coordinates Formula accurate?

Yes. It is highly accurate and used in professional surveying.


FAQ 6: Can it calculate area of irregular shapes?

Yes. It works for any polygon, no matter how irregular.


FAQ 7: What if I have hundreds of points?

Use an online calculator or GIS software. Manual computation is not practical for large datasets.


FAQ 8: Why is it called the Shoelace Formula?

Because the pattern of multiplication resembles lacing a shoe.


FAQ 9: Can I use elevation (Z)?

No. The formula only uses X and Y (2D area).
For 3D surface area, a different method is used.


FAQ 10: What is the difference between perimeter and area calculation?

Perimeter uses distances between points.
Area uses cross-multiplication of coordinates.


11. Final Thoughts

The Area by Coordinates Formula is one of the most important tools in surveying, GIS, engineering, land mapping, and agriculture. It is fast, reliable, and easy to automate. Whether you’re calculating the area of a farm, plot, building footprint, or drone-mapped polygon, this method delivers accurate results every time.

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