Field area measurement
Draw the field on the satellite map and see how many hectares it is, with perimeter and side lengths. Plain distances can also be measured, or the boundary can be walked using the phone's GPS. Nothing leaves the device — everything is calculated locally.
1 On a computer, on the map
- Find the field. Drag the map with the mouse and zoom with the wheel. Or press "Find where I am" to move the map to your position.
- Zoom in enough for the boundaries to be distinct. The closer in, the more accurate the measurement.
- Press the polygon icon, top left on the map. It is the pentagon shape. For rectangular fields, press the rectangle below it.
- Click on each corner of the field, in order, going all the way round. With the rectangle, simply drag diagonally.
- Close the shape: click again on the first point placed, or press the Finish button that appears.
- The area appears immediately below, in hectares, square metres and Greek stremmata.
2 On a phone, with a finger
- The drawing is not done with the finger on the map. In the centre there is a crosshair that stays still. The map moves underneath it.
- Drag and zoom until the crosshair falls exactly on the first corner. The finger never hides the point.
- Press the large "Place point here" button.
- Repeat for each corner. From the third point onwards the area updates live.
- Wrong point? Press "Undo" and only the last one is removed.
- At the end press "Close the shape". There is no need to return to the start — it closes itself.
- When standing in the field, press "At my position" at each corner and the point is taken from the GPS, without looking at the map.
Press the pencil icon at the top left of the map to move corners, or the bin icon to delete a shape. The "Clear" button removes everything and starts again. Several parcels can be measured together — their total is shown as well.
Move the map so that the crosshair falls on the corner and press "Place point here". For drawing with a mouse, switch to "By drawing".
Units and accuracy
The units used
| Unit | Equivalent | Where it is met |
|---|---|---|
| Square metre (m²) | the base | Greenhouses, small parcels, surveying |
| Stremma | 1,000 m² = 0.1 ha | The everyday unit in Greece, used for rates and yields |
| Hectare (ha) | 10,000 m² = 10 stremmata | EU subsidy declarations and scientific literature |
European subsidies and almost all international literature work in hectares, while Greek growers think in stremmata. A rate of "120 kg N per hectare" is 12 kg per stremma, not 120. It is among the commonest and most expensive errors in fertilisation, which is why this page always shows all three units together.
How accurate the measurement is
The area is calculated geodetically, that is taking the curvature of the Earth into account, and not as if the field were on flat paper. At field scale the difference between the two methods is of the order of one thousandth of a percent — negligible. The error does not come from the mathematics, it comes from where the points are placed.
| Method | Typical accuracy | When to prefer it |
|---|---|---|
| Drawing on the satellite image | 1 to 3 metres at the boundary | Almost always. It is the most accurate method when the boundaries are clearly visible |
| Walking with phone GPS | 3 to 10 metres per point | When the boundaries cannot be made out from above — woodland, shade, a fresh planting |
| Land survey | centimetres | When there is a legal or transactional need |
The measurement is for the user's own work — calculating fertiliser, spray volume, plant numbers, yield estimates. It has no legal force. For subsidy declarations the digitised parcel of the official system applies; for contracts and boundary setting a surveyor is required. A measurement that differs from the official declaration does not mean the declaration is wrong: the official parcel often excludes uncultivated strips, tracks and terraces.
Practical points
- Zoom in before drawing. The closer in, the more precisely the corner is placed. The difference between drawing from far away and from close up can reach half a stremma in a one-hectare field.
- Place the point at the middle of the corner, not on the tree. The boundary is where ownership stops, not where the last row of trees stands.
- On a phone, stand still for a few seconds at each corner before pressing. The GPS needs time to settle, and the page shows the estimated accuracy in metres.
- For irregular shapes, place more points. Three corners on a rounded field underestimate the area.
Map. Satellite imagery by Esri World Imagery, street map by OpenStreetMap. The measurement is performed entirely on the device.