Which ArcGIS Desktop extension is needed for calculations using the Block Statistics geoprocessing tool?

The Block Statistics geoprocessing tool is specifically part of the Spatial Analyst extension in ArcGIS Desktop. This tool allows users to summarize cell values from a raster dataset within specified block areas, which is essential for various spatial analysis tasks that involve examining spatial patterns or trends in contiguous data.

Spatial Analyst provides capabilities for raster data processing and analysis, enabling functions such as surface analysis, hydrological analysis, and suitability modeling. The Block Statistics tool effectively utilizes the features of the Spatial Analyst extension to compute various statistical measures (like mean, median, count, etc.) on raster values within defined blocks, making it an essential tool for users who require detailed analysis of raster datasets and spatial distributions.