Upload or photograph a Cadastral Map (नपी नक्सा), calibrate scale, and trace plot boundaries to get accurate areas.
Lay your official blueprint (नक्सा) flat on a well-lit surface. Take a top-down photo without tilting or upload a clear scanned image.
Click two points across a known boundary line or map scale bar. Enter the exact real-world length in feet or meters to establish the pixel scale.
Click corners to outline the parcel. You can drag any pin to fine-tune its exact position on the boundary line.
Click 'Calculate Area' to run the Gauss Shoelace Formula and get immediate results in Ropani, Bigha, Square Feet, and Square Meters.
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Take a photo or upload an image using the buttons above to start tracing
Digital images represent geometry in screen pixels (px). To translate pixels into physical dimensions (feet or meters), the Euclidean distance formula is applied between two calibration points:
This scale factor converts all polygon vertices from screen pixels to physical coordinates (x_real = x_px / S).
The exact area of any non-self-intersecting irregular polygon with n vertices is calculated through coordinate cross-multiplication:
This formula computes the exact area for any convex or concave polygon without requiring manual triangulation.
| System / Region | Unit | Sub-divisions | Square Feet (वर्गफिट) | Square Meters (वर्गमिटर) |
|---|---|---|---|---|
| Hills & Kathmandu Valley (पहाड र काठमाडौं) | 1 Ropani (रोपनी) | 16 Aana | 5,476.00 sq. ft. | 508.74 m² |
| 1 Aana (आना) | 4 Paisa | 342.25 sq. ft. | 31.80 m² | |
| 1 Paisa (पैसा) | 4 Daam | 85.56 sq. ft. | 7.95 m² | |
| 1 Daam (दाम) | - | 21.39 sq. ft. | 1.99 m² | |
| Terai System (तराई क्षेत्र) | 1 Bigha (बिघा) | 20 Kattha | 72,900.00 sq. ft. | 6,772.63 m² |
| 1 Kattha (कट्ठा) | 20 Dhur | 3,645.00 sq. ft. | 338.63 m² | |
| 1 Dhur (धुर) | - | 182.25 sq. ft. | 16.93 m² |
Look for the graphical scale bar printed at the border of your map (usually labeled 1:500, 1:1200, or 1:2500), or identify a straight boundary whose field measurement you have confirmed with a measuring tape. Draw the calibration line across that distance.
Yes. For curved roads, rivers, or canals bordering a plot, place vertex pins closer together along the curve. The polygon algorithm will accurately capture the curvature.
For best accuracy, use a document scanner app (like Adobe Scan) or lay the blueprint completely flat on a table. Angled photographs introduce perspective distortion, which stretches coordinates and can result in measurement errors.