Difference between Geostatistical analysis and Spatial analysis tool for interpolation

Question

I did interpolation on point data using "Geostatistical Analyst" tool. It gives me surface layer. Then I exported this layer into raster image (by right click on this layer=>export data into raster) for convenience of raster calculation. But few minutes ago I found another approach on internet to create raster image from point data. That is to use "Spatial Analyst tool". So I'd like to ask there is any difference with output of further calculation between the two raster images created from 2 difference interpolation approach in Arcgis.

Answer 1

From the website of ESRI:

ArcGIS Geostatistical Analyst complements Spatial Analyst. Most of the interpolation methods available in Spatial Analyst are represented in ArcGIS Geostatistical Analyst as well, but in Geostatistical Analyst, there are many more statistical models and tools, and all their parameters can be manipulated to derive optimum surfaces. Additionally, Geostatistical Analyst provides exploratory spatial data analysis tools not available in Spatial Analyst, such as an interactive wizard that simplifies the interpolation process and provides users with surface previews before applying them. Spatial Analyst has many functions in other areas, such as map algebra, combinational operators, and data conversion.

ArcGIS Geostatistical Analyst expands the number of deterministic and geostatistical interpolation methods and provides many additional options. In particular, Geostatistical Analyst provides a variety of different output surfaces such as prediction, probability, quantile, and error of predictions. Surfaces can be displayed as grids, contours, filled contours, and hillshades or any combination of these renderings. These surfaces can be exported in raster and shapefile formats for working together with other extensions such as ArcGIS Spatial Analyst. ArcGIS Geostatistical Analyst also includes an interactive set of exploratory spatial data analysis tools for exploring the distribution of the data, identifying local and global outliers, looking for global trends, and understanding spatial dependence in the data.

So the version in the Spatial Analyst is a slimmed down version of that used in the Geostatistical Analyst. If you just need a simple interpolated surface, stick to the Spatial Analyst. If you are more serious about interpolation, defintely use the Geostatistical Analyst.

Answer 2

As simply as possible, Spatial Analyst interpolation performs matemathic interpolation based only on the value and distance (so to compute the value of altitude between two points, you can apply a simple method of linear interpolation), while Geostatistical Analyst perform interpolation based on statistical relations between the value and distance (so to compute the value of altitude between two points, you could take into consideration the Earth curvature, and even the real datum). While the first is suitable for topography, the second is suitable for other surfaces, especially when the distance between the points of data is big and irregular.