The authors are studying the possibility of applying remote sensing using drones to rice growth surveys. Conventional growth surveys are based on ground measurements, which are complicated and time-consuming. The authors aim to reduce the labor required for growth surveys and increase the efficiency by introducing remote sensing using drones. Indices obtained through remote sensing include the Normalized Difference Vegetation Index (NDVI) and the Green Normalized Difference Vegetation Index (GNDVI). The authors, who are affiliated with Konica Minolta, Inc., have developed an analysis system to obtain the GNDVI, which is considered to be strongly correlated with ground measurements. To spread the use of the GNDVI at production sites, the authors report here the results of a three-year survey from 2020 to 2022 on the relationship between the GNDVI and the ground measurements. A rice variety named “Kinumusume” was selected for the study. Five ground measurement items were used: plant height, leaf color, number of stems, Leaf Area Index (LAI), and nitrogen absorption amount. Strong correlations with a correlation coefficient of 0.8 or higher were observed for “GNDVI and plant height,” “GNDVI and (plant height × leaf color),” “GNDVI and LAI,” and “GNDVI and nitrogen absorption amount.” The correlation between “GNDVI and number of stems” varied depending on the year. Although a strong correlation was observed for “GNDVI and (plant height × leaf color × number of stems)” in a single year, there were annual differences due to the influence of the number of stems. For an intuitive understanding of the GNDVI, the authors propose that rice plants be represented as three-dimensional objects determined by the plant height, vegetation cover rate, and leaf color.