Photos: fixed photo points and camera diameter
Repeat a fixed-point photo exactly with the earlier photo faded over the camera, and measure a stem diameter from a photo with a reference card — as a proposal you confirm.
- For
- Field crew
- Time
- 4 minutes to read
- Where
- Field app — capture screen
- Updated
On this page
Repeat a fixed-point photo
A photo point is useful only if every later photo is taken from the same place, the same way. The app shows the earlier photo faintly over the camera and tells you how to line up.
- 1 The earlier photo, faded over the live view
- 2 How to line up: bearing, tilt, zoom
- 3 Fade the earlier photo in or out
- 4 Take photo
- Tap the photo field on the plot form (e.g. Fixed-point photo). The earlier photo appears faded over the live view.
- Follow the hints — turn to the bearing (Turn right 6° to 210°), check the tilt and zoom. The pill says Not lined up yet until bearing and tilt match.
- Fade the earlier photo in or out with the slider to compare edges.
- Tap Take photo. Position, bearing and tilt are stored with it.
On the web, photos of the same plot and bearing are paired either side of each intervention — see Before and after photos.
If the earlier photo is not on the phone yet it downloads at the next sync — sync before the visit.
Measure a diameter with the camera
When there is no tape to hand, photograph the trunk at breast height with a card of known width held flat against it.
- 1 Tap the trunk edges, then the card edges
- 2 The proposed DBH — not counted yet
- 3 Reference card width
- 4 Use as proposal
- Tap the four edges on the photo — the two sides of the trunk, then the two ends of the card. The bar shows how far you are (Step 4 of 4).
- Read the proposal. PROPOSED · Camera · Not counted yet: it goes into the form as a proposal, and you accept it there or type the tape reading.
- Check the reference card width (a bank card is 8.56 cm).
- Tap Use as proposal. In the form, Accept, Edit or Reject it like any proposal (Voice notes and proposals).
The camera estimate depends on the card being flat on the stem and the photo square to it. Check a few against a tape before relying on it; a camera value never counts until a person accepts it, and it stays labelled as assisted.
- The camera screens are plain camera views; they were not redesigned as full-screen camera interfaces.
- No automatic edge detection: you tap the edges.
- No AI diagnosis of tree health from photos — decided against.