Lake Okeechobee is a large shallow lake with over 46% (as of 2006) being underlain with phosphorus-enriched mud sediments. Hurricane-induced sediment re-suspension plays a significant role in the nutrient cycling of this lake. It is important to develop optimal geospatial models with low uncertainty to track the distribution and changes of total phosphorus (TP) and total nitrogen (TN) over time (1988-2006). In this book, geographically weighted regression (GWR), ordinary least square (OLS) regression, ordinary/co-kriging, and regression-kriging were calibrated, validated and compared using data sets collected from the Lake in 1988, 1998 and 2006. The GWR models were superior to other models since it uses both spatial auto-correlation and correlation between target variables (TP and TN) and independent variables to improve the model performance. This book is an invaluable resource for GIS professionals, environmental scientists, lake and reservoir managers and graduate students.