I'm working on an analysis that involves summarising a stack of unprojected (WGS84) global 30" climate rasters (various expressions of temperature and precipitation), and generating final output in an equal-area projection.
Is it better to project the individual global rasters first (e.g. to Mollweide) and then summarise, or to summarise and then project? What factors (other than computational efficiency) should be considered in this regard?
Additionally, final output will probably be aggregated to 10 km. Is it more appropriate to aggregate raw data to, say, 0.1° and project to 10 km, or project to ~1 km and then aggregate to 10 km?