Field Geometry measures a field from dimensions you already have or can pace out, saves it, and turns it into a report — for a farmer who knows his field's shape and just needs the arithmetic done correctly.
It is the manual counterpart to Field Mapping's GPS walk. Not every field needs walking: a rectangular plot whose sides are known, or one that can be measured with a tape in ten minutes, does not need a smartphone tracing its boundary.
It handles the shapes real fields actually are — not only rectangles but irregular plots broken into parts — because a field with a road cutting one corner off is the normal case, and a tool that only does rectangles quietly makes a farmer round up.
Measurements are saved rather than discarded, so a field measured once can be reused every season for seed rate, fertiliser quantity and rent, which is where an area number is actually spent.
It produces a report, and it is honest about what that report is: a measurement, not a legal survey. No revenue office is obliged to accept it as a title document, and the tool says so rather than letting anybody assume otherwise.
How to use Land Measurement Intelligence
What it is. Area and perimeter of a field from measurements you take yourself, for five regular shapes — rectangle, square, triangle, circle and trapezium — with the answer given at once in square metres, acres, hectares, square feet, square yards, square kilometres, bigha, kanal and marla.
When to open it. Before you buy seed, order fertiliser, quote for fencing, agree a rent, or argue with anybody about how big a plot is. Any time the honest answer to 'how big is it?' is 'about'.
Have ready.
A tape, a measuring wheel, or a rope of known length. Paces will do at a pinch, and will be out by several percent.
All the measurements in metres. Every input box carries an 'm' after it for that reason.
A name for the field, so the measurement is still identifiable a season later.
Step by step.
Pick the shape that most nearly matches the plot. A field that is a rectangle with one crooked edge is a trapezium, not a rectangle.
Give the field a name — 'North field', 'behind the tubewell'. It is the only thing that tells two saved measurements apart.
Fill in every box the shape asks for. The Calculate button stays off until they are all there, because a formula fed a blank returns an answer that looks exactly like a real one.
Read the area in whichever unit the conversation is being held in. All of them are on the results card at once.
For an irregular plot, choose Polygon. That hands you to Field Mapping, where you draw the boundary on a map or walk it with GPS.
What it will not do. It measures the shape you describe, not the ground. It cannot see the field, cannot know whether your tape was straight, and cannot tell you what a revenue record says. Where a land record and this disagree, the record is the authority.
Every setting in Land Measurement Intelligence, explained
Field / plot name
A label for this measurement. How to choose: What you and the people you work with actually call the plot. If it is wrong: Nothing is miscalculated, but a list of saved fields called 'Field 1' through 'Field 6' is a list you will not use.
Length and Width (rectangle)
The two adjacent sides, in metres. How to choose: Measure both, do not assume. A field that looks square is rarely square. If it is wrong: Area is out by the same proportion as the error. Over-measuring one side by 5% over-orders 5% of every input you buy by area.
Side (square)
One side, in metres. How to choose: Only use Square if you have checked that the other three sides match. Otherwise use Rectangle and measure two. If it is wrong: A 98 by 102 metre plot called a 100 metre square is 4 square metres out — trivial. A 90 by 110 called the same is not.
Side A, Side B and Side C (triangle)
The three edges of a triangular plot, in metres. The area is worked out from them by Heron's formula. How to choose: Walk all three edges. This is the reason the tool asks for sides instead of a base and a perpendicular height: three edges can be measured with a tape by one person, whereas a perpendicular height needs a right angle established out in the field, and in practice it gets guessed. If it is wrong: Three lengths where one is longer than the other two put together do not make a triangle at all. The tool refuses rather than printing a number, and asks you to check the measurements.
Radius (circle)
Centre to edge, in metres — not all the way across. How to choose: If you measured the full width, halve it before typing. Centre pivot irrigation is the usual reason this shape gets picked. If it is wrong: Entering the diameter gives four times the real area, because area goes with the square of the radius. It is the single easiest mistake on this screen to make and the hardest to spot, because the answer looks plausible.
Top Base, Bottom Base and Height (trapezium)
The two parallel edges and the perpendicular distance between them, in metres. How to choose: The height is the straight distance across between the two parallel sides, not the length of a slanting edge. If it is wrong: Using a slant edge as the height overstates the area, always.
Left Side and Right Side (trapezium)
The two slanting edges, in metres. They do not affect the area; they are what makes the perimeter real. How to choose: Measure them. Top, bottom and height describe an unlimited number of trapeziums with different edges, so the perimeter genuinely cannot be worked out without these two. If it is wrong: The perimeter comes out short, which matters the moment somebody orders fence or drip line against it.
A worked example
A plot with one crooked edge: the two parallel sides measure 30 m and 50 m, the distance across between them is 20 m, and the two slanting edges are 22.36 m each.
What goes in:
Shape: Trapezium
Top Base 30
Bottom Base 50
Height 20
Left Side 22.36
Right Side 22.36
What comes out:
Area 800.00 m²
0.1977 acres, 0.0800 hectares
8,611 square feet
Perimeter 124.72 m
The perimeter is the number to take to the fencing shop, and it is 124.72 m rather than the 100 m you would get from the two parallel sides and the height alone. Those two slanting edges are a quarter of the fence.
How to read what it gives you
Area and perimeter answer different questions. Area buys seed, fertiliser and spray; perimeter buys fence, bund and boundary drip.
Acre and hectare are exact conversions. Bigha is not — it has no national standard and the figure shown uses one common approximate value. Read the Area Calculator page before relying on a bigha figure.
The area is of the shape you told it, not of the field. If the plot is not really that shape, the answer is precise and wrong.
For anything irregular, walking the boundary in Field Mapping will beat fitting a rectangle to it, every time.
What usually goes wrong
Entering a circle's diameter where it asks for radius. The area comes out four times too big.
Using a slanting edge as the trapezium's height. The height is the perpendicular distance between the parallel sides.
Mixing units — pacing one side and taping another, or entering feet in a box marked m. Everything must be metres.
Forcing an irregular field into a rectangle because it is quicker. Two crooked edges can easily be 10% of the area, which is 10% of every input you buy for it.
Questions people ask about Land Measurement Intelligence
How do I calculate the area of a triangular field?
Measure all three sides and enter them. The area is worked out by Heron's formula, which needs only the three lengths — no right angles, no perpendicular height. A 3-4-5 triangle, for instance, comes out at exactly 6 square units.
Why does it ask for the slanting sides of a trapezium when they do not change the area?
Because the perimeter cannot be worked out without them. The two parallel sides and the height describe infinitely many trapeziums, all with the same area and different edge lengths. If you are fencing the plot, those two edges are the difference between ordering enough wire and not.
How accurate is it?
The arithmetic is exact. The accuracy is entirely your measurements: a tape on flat ground is good to well under one percent, and paced distances are commonly out by five. Nothing in the app can improve a measurement after it has been typed in.
How do I measure a field that is not any regular shape?
Choose Polygon, which opens Field Mapping. There you either draw the boundary on the map or walk it with the phone's GPS, and the area is computed from the real boundary rather than from a shape fitted over it.
Does it work without an internet connection?
The five measured shapes are pure arithmetic and work offline. Polygon needs the map, so it needs a connection.
Can I use this for a land record or a legal document?
No. It is a measuring aid. A revenue record, a registered survey or a licensed surveyor is what a legal document needs, and where any of those disagree with this, they are right and this is not.