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Parcel area and side lengths from corner coordinates
Paste the corner coordinates from a Vietnamese land certificate (VN-2000) or latitude and longitude (WGS-84), in order around the parcel, to get the area, perimeter, each side length, the angle at each corner and a drawing. The area is computed on the VN-2000 plane, the way certificates are drawn up, so it can be checked against the certificate.
How to use it in 3 steps
- Choose the coordinate system: VN-2000 (with the province) or WGS-84.
- Paste the corners in order around the parcel; optionally enter the certificate area.
- Press Compute area; read the shape, sides and angles; open it on the Vilac map or download KML, DXF.
Method
The area uses the polygon (shoelace) formula on plane coordinates. VN-2000 X, Y are used as printed. WGS-84 corners are first projected onto a plane centred on the parcel; the result differs by less than 0.05% from the VN-2000 computation. Crossing edges, usually corners out of order, are flagged.
Frequently asked questions
Why does the area differ slightly from the certificate?
Certificate coordinates are rounded to the centimetre and the area to 0.1 m². A difference of a few parts per thousand is normal; a few percent suggests corners out of order or the wrong province.
In what order should the corners be?
In order around the parcel, as listed on the certificate; clockwise or anticlockwise both work. No need to repeat the first corner.
Does the province matter for the area?
No. Area and sides are computed on the VN-2000 plane; the province only sets where the parcel is on the map.
How do I view the parcel on the Vilac map?
Press View on the Vilac map: the map opens at the parcel and shows the outline under My drawings.
Are the coordinates stored?
They are not sent to a server; the outline is kept only in this browser tab for the map.