Aggregating spatio-temporal raster data
Spatio-temporal data, such as MODIS images, time series, or meteorological records from several stations (see Chapter 3, Working with Tables) pose a challenge for analysis and visualization due to their three-dimensional nature. One approach to simplify such data is to perform aggregation in spatial and/or temporal dimensions (another approach to simplify spatio-temporal data is, for example, cluster analysis).
In this section, we will experiment with two approaches to aggregate the data held in the multiband raster r
in order to get additional perspectives on the spatio-temporal behavior of NDVI within the geographic area this raster covers.
Note
More specialized classes and methods (including aggregation) for various types of spatio-temporal data are defined in the spacetime
package. An overview of this package can be found in the introductory paper "spacetime: Spatio-Temporal Data in R" by its creator Pebesma E. 2012.
The time dimension
In our first...