Fig. 4

Four variance specification methods employed in geolocation of simulated fish movement trajectories. a Standard deviation of fine-scale map (100 m) values within each 1 km aggregated fine-scale model grid; b the roughness method of obtaining variance (standard deviation of all adjacent cells) for the coarse-scale map; c the slope method of determining variance by relating fine-scale map values to the slope of the coarse-scale map, and d variance specification based on the root mean square difference between measured and mapped values by magnitude of anomaly (see Fig. 5). Islands and convoluted shorelines have been removed to simplify the simulation exercise