To achieve a measurement with high spatial resolution over a large area, we stitch together multiple high spatial resolution maps obtained from an interferometric microscope with or without a motorized stage. These maps have a high height precision and a lateral resolution as high as 0.11 micron/pixel. They can be stitched together with acceptable accuracy as long as each of their adjacent areas has enough overlapping pixels. The stitching technique we have developed is based on a computed probability that gives a quantitative measure for the goodness of the chi-square fitting. It is insensitive to the piston and tilt changes of each map. It is also insensitive to the lateral shift and/or rotation between the overlapping maps. This technique is robust and flexible. It is able to give a satisfactory measurement without relying on the accuracy of the stage movement. The map stitching expands the field of view available to an objective lens, which makes it possible to measure a large area without losing high-slope surface features.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.