Precision - The size of the deviations between repeated estimates of a given statistic.
Process-colour printing - Output derived by overprinting selected values of additive primary colours.
Proxy data sources - Historical records or measurable properties of biological, chemical or physical systems, that provide quantitative information about past environmental conditions. Biotic proxies are based on the composition of plant and animal groups and/or measures of their growth rates; geological proxies quantify changes (physical or chemical) in Earth’s materials that have accumulated through time, most commonly sediments in oceans or lakes, or ice in polar or alpine glaciers; historical proxies are records of events such as droughts, floods or harvest yields.
Range - The limit of spatial dependence in the semi-variogram, that is, the lag at which the sill is reached.
Raster map - Particularly useful for data produced routinely from satellites where values are recorded for equal areas associated with grid squares or pixels on a computer screen. Raster data can usually be entered into a GIS directly as numbers from the keyboard.
Ratio data - A measurement level indicating precise distances between observations and with a non-arbitrary starting point.
Reflexivity - Critical and conscious introspection and analytical scrutiny of oneself as a researcher. Reflexivity is not simply ‘navel gazing’; it is examining our own practice in order to gain new insights into research.
Regionalized variable - The outcome of many randomly located samples of a property in space, assumed to be the statistical realizations of a set of random variables, or a stochastic process.
Remote sensing - The collection of images of parts of the Earth’s surface using specialized instruments, commonly aerial cameras and satellite sensors.
Sampling - The acquisition of information about a relatively small part of a larger group (population), usually with the aim of making inferential generalizations about the larger group.
Scale-linkage - Phenomenon whereby things of one size and/or time-span are composed of objects and time periods that are smaller and, in turn, are themselves formative components of larger assemblages and/or time periods.
