Department of Statistics, Tarbiat Modares University, Tehran, Iran
In spatial data analysis, the variogram function that determines the correlation structure is usually unknown, and most estimates based on observations. The presence of outliers affect on the estimation of the variogram function, trend parameters and spatial prediction. In this paper some new robust estimators of variogram are presented. The proposed estimators have highly breakdown points and are based on scale estimators. All proposed estimators are assessed based on simulation studies. In addition robust methods of trend estimation and spatial prediction are presented. Finally, a real world problem about the average temperature of 170 cities in Iran is analyzed using discussed methods.