Spatial econometrics has relied extensively on spatial autoregressive
models. Anselin (1988) developed a taxonomy of these models using a re
gression model framework and maximum likelihood estimation methods. A
Bayesian approach to estimating these models based on Gibbs sampling i
s introduced here. It allows for non-constant variance over space taki
ng an unspecified form and outliers in the sample data. In addition, e
stimates of the non-constant variance at each point in space allow inf
erences regarding the spatial nature of heteroskedasticity and the pos
ition of outliers.