What separates what we see from what is actually there? Sheung Yiu’s Ground Truth takes that old photographic question into the forests of Finland, where a team of scientists works at the limits of satellite imaging. Their tool is measurement on the ground — the physical structure and spectral properties of individual trees — gathered so that predictive models can be tested against something real. In remote sensing, “ground truth” names exactly this: the field data that tells us whether a model’s reading of the surface can be trusted.

Yiu builds the book from heterogeneous materials: archival imagery, documentary photographs, experimental data, and his own artistic work. Rather than illustrate a research project from the outside, the sequence acquaints the reader with the mathematical models that allow trees to be reconstructed from two-dimensional images, and asks what it means to distinguish features of a landscape that the eye never registers in a satellite photograph. As computation grows more powerful, seeing becomes more abstract; the book keeps that paradox in view.

Ground Truth is a collaboration as much as a monograph. Yiu provides concept and photography; Miina Rautiainen, Daniel Schraik, Aarne Hovi, and Petri Forsström contribute research and essay material; Yiu writes the text. Emery Norton designed the volume, drawing on the Finnish Forest Museum (LUSTO) and the Finnish National Gallery Kiasma, with lithography and production by Wilco Art Books.

The Eriskay Connection issued the book in 2021: 200 pages in English, 170 × 240 mm, in a classic softcover with a separate cahier. For collectors drawn to photography that thinks about its own conditions of evidence, the book pairs a timely subject with an unusually disciplined collaboration between artist and scientists, and a design that holds documentary, archival, and data materials in one considered sequence.