How to calculate field area: square metre, decare, dönüm and hectare
Field area seems simple: walk the boundary, close the polygon and read the area. The details decide whether the number is useful.
Field takeaways
- 1 decare is 1000 square metres; 1 hectare is 10,000 square metres.
- Phone GPS is useful for approximate field area, not official parcel area.
- A polygon must close and the boundary source must be noted.
- Clean geometry produces more reliable area.
- MapLab Survey stores area, perimeter, layers, notes and export together.
Get the units straight first
One decare is 1,000 square metres; one hectare is 10,000 square metres, or ten decares; one square kilometre is a hundred hectares. In Türkiye the word "dönüm" dominates field conversations and in daily speech usually means a decare — but a technical delivery should say square metres, decares or hectares explicitly, because "12 dönüm" alone is not precise enough in an official context.
Which boundary is the area computed from?
This is the most important question. Did you walk inside the fence, along the occupation line, on the cadastral parcel line, on a design line, or between corners measured with RTK? On the same land these boundaries differ, and each gives a different area. Writing the boundary source next to the result is the professional habit that prevents the argument later.
Measuring the polygon
When drawing the polygon in MapLab Survey, do not over-densify the corners. A point every metre along a straight fence does not make the area more accurate — it sometimes adds GPS wander instead. Capture the break points, the gate turns, the ditches and the corner changes; close the polygon; check the area and perimeter; attach photos and notes.
Approximate area and official area are different products
An area walked with a phone serves agricultural planning, irrigation scouting, fence costing and rough progress checks perfectly well. It should not stand alone in expropriation, a sale, a court case or a cadastral procedure — those need the authority's data, control points and measurement that meets the regulations. Determining an official boundary is licensed survey engineering work; the app speeds up the field side and does not replace the side that signs.
Deliver the number with its story
The finished figure travels best as a small package: the polygon itself as KML or DXF, the unit written out, the boundary source named, and the method noted. A number with its story survives scrutiny; a bare number invites it.
Try these steps on your own phone.
MapLab Survey handles RTK/GNSS point capture, drawing, area and volume calculations and coordinate conversion, then exports to DXF, KML/KMZ, GeoJSON, Shapefile, GeoPackage, NCZ or CSV. Capture, calculation and export work offline. Live NTRIP corrections and online basemaps need a connection.
Frequently asked questions
How many square metres is 1 decare?
1000 square metres.
How many decares is 1 hectare?
10 decares.
Can a phone measure field area?
For approximate planning, yes. Not as official parcel area.
What matters most?
The boundary source used for the polygon.
Technical references
The field guidance in this article is aligned with the technical and official references below.
Related: Phone area measurement · Finding parcel corners · How to measure land · MapLab Survey