Hello. Recently, I started to develop regression models using spatial data. In particular, I've been developing mixed-effect models. My data requires to take into consideration spatial autocorrelation, so I decided to use the corStruct function in the nlme library. Once I built a variogram plot to analyze the autocorrelation, though, the data (pairs of locations) have a semivariance (y axis value) that goes above 1. It looks like the corStruct spatial correlation models are forced to level out at semivariance = 1. This way, the curve (Gaussian is the closest fit) does not fit my data. Here is the variogram plot: http://r-sig-ecology.471788.n2.nabble.com/file/n7577462/gaussian.jpeg Does anybody know how to solve this problem? Hope I'm not misusing the function. Alessia -- View this message in context: http://r-sig-ecology.471788.n2.nabble.com/spatial-correlation-in-mixed-effect-models-tp7577462.html Sent from the r-sig-ecology mailing list archive at Nabble.com.
spatial correlation in mixed-effect models
1 message · aletsia83