Analysis of Topographic Effects on Vegetation Indices

In the field of remote sensing, vegetation indices (VIs) have been wieldy used in vegetation monitoring such as the growth status and fractional vegetation cover. However, topographic influence on VIs is an important and inevitable issue when VIs are applied in the large scale. In this study, theoretical error analysis of topographic effects is applied to various VIs. This error analysis suggests that ratio indices (e.g., NDVI, NDPI, NDWI) are more resistant to the topographic effects than the non-ratio indices (e.g., EVI). Also, single-slope experiments are designed by changing local slope and local incident angle with 3D radiative transfer model to simulate the topographic effects on VIs. Results of simulation experiments can verify the error analysis.