Extract stats from a given area using spatial data. How much did it rain?

In this blog post you will learn how to extract stats from spatial data to respond to questions like: how much did it rain in a given catchment last year? what is the dominant land use/forest type in a given area (e.g. region)? what is the total population of a given area?

 Why is this type of data/information important in Ecology? Most of the time, a phenomenon that is observed at a given spot (e.g. % of organic matter in a given river segment/strech) depends not just on what´s happening in that particular place (e.g. is there livestock using that stretch of the river for drinking? or is there any kind of punctual discharge of organic matter at that place?) but also on what´s happening in its surroundings or other connected parts of the landscape (e.g. how much did it rain in the upper parts of the catchment last week? after a heavy rain lots of nutrients can be washed out from the soils to streams increasing the loads of organic matter).