Abstract: Data, including a plurality of spatial positions of a device that moves through the space, at least some of the positions being positions along the boundary, is accessed; a physical measurement of a region at the boundary is accessed; a determined measurement of the region at the boundary, the determined measurement being based on a subset of the plurality of spatial positions; comparing the physical measurement and the determined measurement, is accessed; a correction based on the comparison is determined; the correction is applied to at least some of the plurality of spatial positions to generate corrected spatial positions; a diagram of the space based on the corrected spatial positions is generated; and the diagram of the space is presented.