How accurate is an area measured in Naapi?
As accurate as the map and the scale. On a portal PDF whose lines are drawn — most of them — the plot outline is taken from the drawing itself, and with the right scale the area agrees with the recorded rakba to within a fraction of a percent for a regular plot. On a scanned or photographed sheet the outline is traced through pixels and the paper, the scan and the line thickness add up to a percent or two. Set the scale from a plot of known area and the systematic part of that error disappears. The arithmetic itself is shown three ways (shoelace, triangles, kanghi) and they always agree; what can differ is the outline and the record — see why a measured area differs from the rakba.
Can I use the figure in court or for a sale deed?
Not by itself. A measurement from a scanned map is a working estimate of what the map shows; the legal record is the khatiyan or jamabandi and the amin's measurement on the ground. Naapi's report is useful to prepare for those — to know what to expect, to check a figure you were given, to plan a division — and every report says so. A batwara drawn in the app is a planning estimate, not a partition.
Which maps work?
Any picture of a cadastral sheet: the CS, RS and Chakbandi PDFs from Bihar's Bhu-Abhilekh portal (best, because their lines are drawn), a scan or photograph of a paper map, a screenshot of Bhu Naksha, a satellite picture. Maps from other states work too; only the default scale (1 : 3,960) and the katha presets are Bihar's, and both can be changed.
Does it cost anything?
No. Naapi is free to use in the browser, with no advertising and no account needed for the map tools. The shared map library needs a sign-in unless the owner has opened it; the Google satellite map is available when the owner has enabled it.
Do I need to install anything?
No. It runs in the browser on a phone, tablet or PC. Install app (in the ⋮ menu, or the browser's install prompt) puts it on the home screen and lets it open offline; there is also an offline Windows build for an office without internet.
Does it work offline?
Yes, after the first visit. Opening maps, finding and drawing plots, measuring, dividing, the calculator, saved projects and the printed report all work without a connection. The OCR engine for scans downloads once (about 8 MB) the first time a map is opened and is kept. Only the shared library, the Google satellite map and place search need the internet.
Where does my map go? Is anything uploaded?
Nowhere. The map file and your plots stay in the browser's storage on your own device. Nothing is sent to a server unless you ask for something from one — a sheet from the library comes down to you, and the Google map and place search contact Google only when you open them. There is no analytics script on the site.
How do I find my plot on the map?
If you know the khesra number, type it under 2 Find plot — the number is found in the PDF's text and the boundary around it is followed. Otherwise switch to Auto-detect and click inside the plot, or Draw its corners. On a scan, press Read plot numbers (OCR) first. The manual shows all three.
The area I get is not the rakba in my papers. Which is wrong?
Possibly neither. Check the scale first (a plot of known area is the best check), then which katha the papers meant — the same bigha-katha-dhur is a third larger in Vaishali than in Patna — then whether the plot has been divided or sold since the survey, so that your paper describes a share. How to read a mauza naksha lists the reasons in order.
Can it divide a plot between heirs?
Yes: into equal parts, by ratio, by a fixed area, or along a line you draw — straight, bent or curved — starting from any side, parallel to a side, or at an angle. The pieces become plots of their own with their areas, and the report prints them. It is a plan for the family and the amin to agree on, not the partition itself.
What about katha and dhur — which value does it use?
By default 4.58 dhur to the decimal, so 1 katha = 1,902.18 square feet, the working value in Vaishali; presets for 1,361.25 and 720 square feet are one tap away, and every number is editable in the Units fold. Decimal, acre and hectare do not depend on this. See the units page.
How is Naapi different from Bhu Meter and the GPS area apps?
Those measure by walking a boundary with the phone's GPS or by typing side lengths, and some convert units. Naapi starts from the map you already have — the cadastral sheet — finds the plot by its number, and measures the drawing; it also does the GPS walk, the typed-length shapes and the unit conversion, lays sheets over each other and over satellite imagery, and works offline in Hindi. Measuring the naksha is the part the others do not do.
Where do I get the map of my village?
From the Bhu-Abhilekh portal of Bihar's Directorate of Land Records and Survey, which holds the CS, RS and Chakbandi sheets as PDFs — the portals page walks through it — or from Naapi's shared library if your mauza has been loaded.