Temporal analysis: Integration
Integrating data from different sources and scales
One of the main challenges of a temporal analysis is to integrate data from a wide range of sources with varying levels of reliability in order to detect genuine changes in the catchment, floodplain and river channel. This is where a geographical information system (GIS) becomes particularly useful. In a GIS, we are able to import graphical data based on any geographical projection of the Earth’s surface, register the data to the current projection, and assess positional accuracy. A GIS can be used to store information for a specific location, e.g. a point on a map can represent a gauging station, and its attributes can be, for example, key characteristics of the flood regime. Once the datasets are correctly loaded into a GIS, they can be queried and analysed using a veritable toolbox of techniques.
A chronology (i.e. time-chart) to visualise the changes that have occurred in the catchment, riparian corridor and channel over time provides a useful way of synthesising changes and their potential causes. The chronology pulls together information on the characteristics that influence geomorphological processes and those that respond to changes in those processes. This allows changes in characteristics to be tracked over time (e.g. land cover, riparian vegetation, human interventions, channel discharge, major flood or drought events, planform pattern, channel width, etc.) and also to explore the causal linkages between them.