A method includes: capturing, via a navigational sensor of a mobile automation apparatus, three-dimensional point cloud data depicting a portion of an aisle containing a support structure, the support structure having a forward plane facing into the aisle; generating, from the point cloud data, a two-dimensional projection in a facility coordinate system; retrieving, from a stored map, an expected location of the forward plane of the support structure in the facility coordinate system; selecting, from the projection, a subset of regions satisfying a positional criterion relative to the location of the forward plane; determining, based on the selected subset of regions from the projection, an actual location of the forward plane of the support structure in the facility coordinate system; and providing the actual location of the forward plane to a navigational controller of the mobile automation apparatus.