Revisiting and Updating the Calculation of the Integrated Moisture Index
Published online on April 18, 2026
Abstract
["Transactions in GIS, Volume 30, Issue 2, April 2026. ", "\nABSTRACT\nThe integrated moisture index (IMI) was developed to indicate long‐term soil moisture potential from data collected in southeastern Ohio. Like the topographic wetness index, the IMI is derived from terrain characteristics that influence the downslope movement of water, with the addition of soil water‐holding capacity. The combination of terrain and soil characteristics provides improved mapping of potential soil moisture. Since the development of the IMI, advances in soil data and geographic information systems warrant revisiting the original methods and modifying the calculation. I provide background information about soil moisture metrics while incorporating new data and techniques to calculate the IMI. Evaluating the transferability of the index to other regions by comparisons to ecological patterns among soil drainage, landforms, and existing vegetation may increase its use for other applications. The resulting IMI is comparable to the original but provides continuous data values and has a broader application than the data from Ohio.\n"]