A bird or wildlife sighting log with the location precision stated: Darwin Core fields for a personal notebook

Goal

Keep sightings in a form where each one says when, where and how precisely, who saw what and how sure they were, so that the notebook can later be compared with someone else's or exported to a database without re-interpreting old entries.

Prerequisites

Darwin Core, the vocabulary used by biodiversity databases, defines the fields this protocol reuses: eventDate (ISO 8601 recommended), decimalLatitude and decimalLongitude in decimal degrees on the spatial reference system named in geodeticDatum (an EPSG code such as EPSG:4326 is recommended), coordinateUncertaintyInMeters as the radius of the smallest circle containing the whole location, for which zero is not a valid value, individualCount, basisOfRecord (HumanObservation for a sighting) and dataGeneralizations for cases where shared coordinates were deliberately coarsened. GPS.gov states that GPS-enabled smartphones are typically accurate to within a 4.9 m radius under open sky and that accuracy worsens near buildings, bridges and trees.

Steps

1. Header per notebook: observer name or initials, the devices used for position (phone model and app, or a paper map and its scale), and the field list below.
2. Per sighting record eventDate with time and time-zone offset (2026-05-03T07:42+02:00), the species name as the observer would write it plus a confidence word from a fixed set (certain, probable, possible, unidentified), individualCount or a stated estimate, and behaviour or life stage in a short note.
3. Record the coordinates of the animal, not of the observer, when they differ, and say which one was taken. Record geodeticDatum once in the header if every position comes from the same device.
4. Record coordinateUncertaintyInMeters per sighting from how the position was obtained: the app's displayed accuracy if it shows one; a larger value chosen by the observer for a bird seen at distance or a position taken under trees; the half-width of a named area when only "the north pond" is known. Never write zero.
5. Link evidence: photo or sound-file name, or "none".
6. When a sighting's location must not be shared precisely, keep the exact entry in the notebook and add a dataGeneralizations note describing how the shared copy was coarsened (for example to a 1 km grid cell).

Expected result

A log whose columns map onto Darwin Core terms, in which every position carries a stated uncertainty and every identification a stated confidence, and in which generalised locations are marked rather than silently rounded.

Limits and test basis

Proposed protocol; no sighting data or accuracy figure of the observer's own devices is claimed. Species identification quality is the observer's, and the confidence word records it rather than improving it. Database acceptance rules vary and are not described here.

Observer position, distance and bearing

Record the observer's coordinates as the device measured them, with the device's displayed accuracy, and put the animal's position in two separate fields: an estimated distance (with the unit) and a bearing or a plain direction, marked as estimates. Set coordinateUncertaintyInMeters to the device accuracy plus the estimated distance, so the circle around the measured point contains where the animal was, which is how Darwin Core defines the term. Do not write a computed animal position into the coordinate fields; it hides an estimate inside a value that reads as a fix. Whoever needs the animal's point later can derive it while the estimate stays visible.