Field photography and satellite radar for verifying alternate wetting and drying in Balinese subaks: data, code and figures

Data, analysis code and figures supporting a study of how alternate wetting and drying irrigation can be verified in smallholder rice terraces, using farmer-taken GPS photographs classified by a vision-capable language model alongside Sentinel-1 C-band and NISAR L-band radar. The deposit covers two Balinese irrigation communities: Subak Bena in the 2024 dry season, with ten fields of 0.08 to 0.36 ha, and Subak Kloncing in the 2026 season, with 33 paired fields over six photographic rounds. It includes field boundaries, photographic classifications with the classifier's reasoning text, a reliability analysis of the classifier itself, radar extractions in raw and orbit-corrected form, and the scripts behind the published figures. At the scale of an individual terrace, radar backscatter does not distinguish flooded from drained fields at either wavelength. At the scale of the irrigation community it detects synchronised drying clearly. The deposit also documents two systematic effects that can produce apparent field-scale detections: an offset of 1.0 to 1.7 dB between Sentinel-1 relative orbits, and thresholds fitted to the labels against which they are validated. The field photographs themselves are not included: they record identifiable smallholdings at precise coordinates, and are available on request subject to the consent of the communities that produced them.