What must match when performing an overlay raster analysis?

In overlay raster analysis, it is essential that cell sizes match in order to ensure the data from different raster layers can be accurately combined and analyzed. Raster data is composed of a grid of cells, with each cell representing a specific value or attribute for that location. If the cell sizes differ between the raster layers, it can result in misalignment or distortion of the data when layers are overlaid, leading to inaccurate analysis and output results.

Matching cell sizes ensures that each corresponding cell within the layers represents the same spatial area, allowing for correct comparison and calculation of values. For example, if one raster has a cell size of 30 meters while another has 10 meters, overlaying them without adjusting would mix data from different spatial resolutions, potentially skewing the results of the analysis.

In contrast, while projection systems and coordinate systems also need to align for meaningful analysis, their alignment primarily pertains to the spatial referencing of multiple data sources; however, it is the cell size that directly impacts the resolution and accuracy of the overlay process itself. Data types must also be compatible, but matching cell sizes is paramount for meaningful raster analysis.