An improved method of wafer height mapping using a wafer level sensor eliminates or substantially minimizes the “spacing” in the wafer height mapping data usually caused by having an exposure field on a wafer whose width is less than the width of the measurement spot array of the wafer level sensor and also not being a multiple of the width of a single measurement spot. According to the improved method, the measurement spot array is first translated towards one edge of the exposure field and scanned. Then the measurement spot array is translated towards the other edge of the exposure field and scanned second time to map the area that was missed during the first mapping scan.