A modified diffusion-limited aggregation model that includes a uniform drift simulates the process of electrodeposition. Through a systematic variation of the model’s parameters, aggregates (electrodeposits) grown under different simulation conditions (experimental conditions of the voltage, current density, and concentration) develop as open dendritic or as compact mossy forms. The resulting aggregate morphologies are characterized by geometric quantities derived from the aggregate particle position distribution. Power laws relate the geometric quantities to each other. Ohm’s law is obeyed to lowest order in the aggregate surface curvature where the curvature is an effective conductivity. The distribution of open sites and its moments, which are geometric quantities, are introduced. © 1997 The American Physical Society.