Shoelace Formula:
where \( x_6 = x_1 \) and \( y_6 = y_1 \)
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The shoelace formula (also known as Gauss's area formula) is a mathematical algorithm to determine the area of a simple polygon whose vertices are defined in the plane. It's called "shoelace" because of the cross-multiplication pattern that resembles shoelace weaving.
The calculator uses the shoelace formula:
Where:
Explanation: The formula works by summing the products of x and y coordinates in a specific order, then dividing by 2 to get the area in square feet, and finally converting to acres.
Details: Accurate land area calculation is essential for property assessment, agricultural planning, construction projects, and legal documentation.
Tips: Enter the coordinates of all 5 points in order (either clockwise or counter-clockwise). The points must form a simple polygon with no intersecting sides.
Q1: What units should I use for coordinates?
A: This calculator expects coordinates in feet. If your measurements are in other units, convert them to feet first.
Q2: Does the point order matter?
A: Yes, points must be entered in consecutive order around the perimeter. Clockwise or counter-clockwise is fine, but they must be in order.
Q3: Can I use this for more than 5 sides?
A: This specific calculator is for 5-sided plots only. The shoelace formula can be extended to any number of sides.
Q4: How accurate is this method?
A: The method is mathematically exact for the given coordinates. Accuracy depends on how precisely you measure the points.
Q5: What if my polygon crosses itself?
A: The shoelace formula only works for simple polygons (no crossing lines). For complex shapes, you'll need to break it into simple polygons.