GPS tree survey app: improving field location accuracy

What a phone GPS reading actually represents

A phone estimates its position using satellite signals and, where available, assistance from Wi-Fi and mobile networks. The latitude and longitude are the estimated centre of the fix; the reported horizontal accuracy describes the expected uncertainty around that estimate.

Dense canopy, buildings, steep terrain, the way the phone is held, and the time allowed for the receiver to stabilise can all affect the result. Two readings taken seconds apart may therefore have different coordinates and accuracy values.

A repeatable field method

• Enable precise location and high-accuracy location services before reaching the site.
• Stand close to the mapped tree while keeping a safe and reasonably open view of the sky.
• Wait for the accuracy value to stabilise instead of saving the first available coordinate.
• Avoid recording beside a vehicle, large metal structure, or building wall when practical.
• If the accuracy remains poor, save the reported value and flag the record for later map review.

Accuracy thresholds must match the purpose

There is no universal phone-GPS threshold that guarantees a precise tree location in every environment. A broad greenbelt inventory may accept a different threshold from a repeat monitoring project that must relocate an individual stem.

Project administrators should define the expected accuracy, train the team, and review outliers on a map. Where centimetre-level or survey-grade positioning is required, use appropriate external GNSS equipment and a qualified geospatial workflow rather than relying only on a consumer phone.

Keep location evidence connected to the record

Enotree stores coordinates with the tree record and lets administrators view survey points in the project context. A photograph, capture time, tree code, and surveyor identity make the point more useful than a coordinate copied into an unrelated spreadsheet.

Location data is sensitive. Access should remain project-scoped, exports should be shared intentionally, and surveyors should collect coordinates only for authorised work.

Frequently asked questions