Granularity Flashcards
What questions does granularity information respond too?
Granularity information answers question about the level of detail on spatial information.
For example, how precisely a smart phone can locate itself
What questions is granularity information answering?
Granularity information answers questions about the level of detail and the concept of information quality used to describe information rather than phenomena of the world.
Why does granularity matter in decision making?
Granularity matters for example in adsessingg whether demographic data or climate data have enough spatial detail to support a certain policy decision. Together with accuracy granularity measures how uncertain some information is.
How can granularity increase accuracy?
Reducing granularity I.e. turn it into a less detailed but more certain information. For example, if you visit a foreign city and do not know exactly where you are, you might say I’m near the city centre.
What is granularity information?
The notion of granularity or grain size at which one described something is fundamental for thinking and computing. The term granularity refers to the level of detail affecting any stage of producing or using spatial information-starting from conceptualisation to representation and analysis and visualisation.
Refers to silver grain emulsion limited to the smallest recordable entities, and the idea of grain of wheat serving and the smallest unit of weight in ancient measurements.
What is the difference between resolution, precision and granularity?
Resolution refers to the granularity of observations e.g. of a satellite image emphasising each observation is an aggregate of phenomena at finer details. Precision refers to the number of digits Unser in reporting a measurement). Granularity is the level of detail affecting the use or production of spatial information.
Why do we not use the term scale?
The term scale has so many different and conflicting meanings that it is best used as an informal notion only.
How can representations using different granularities be useful?
Representations of the same reality can differ vastly at different granularities. Computations performed on such different representations can produce very different and even contradictory results. This means one can solve problems at adequate granularities, rather than carrying around unnecessary detail or gnotobiotic relevant information.
Give an example of a spatial, temporal and thematic limit to granularity.
Information gained from satellite images had the spatial resolution of the distance on the ground corresponding to the inside pixel, the temporal resolution of the exposure time, and the thematic resolution resulting from its spectral bands. These resolution values impose s lower limit on the granularity in space time and theme of information derived from the images.
What is thematic granularity?
Thematic granularity deals with the level of thematic detail.
Give some examples of how granularity characterises all concepts of spatial information?
Location is recorded at certain spatial and temporal granularities, field are recorded in discrete spatial and temporal grids, the choice of object types (say buildings vs cities) determines the spatial granularity of object information; the choice of node and edge types defined the level of detail of network information, and events are defined and distinguished by choosing a temporal granularity(a sand storm vs soil erosion).
How is granularity represented?
Cell size in raster day
minimum mapping units for polygons
Coordinate precision (number of decimal places)
Administrative, statistical or census units.
How is granularity used?
Generalisation
Aggregation
What are the issues with granularity data?
False precision- storing, displaying or calculating more decimal places than the original precision. Within any given coordinate system, an important question is how precisely one should locate something
Having too detailed a granularity to compromise personal data.
The granularity of postal codes is not constant. In some locations can be a few regions per country to millions of elements with sizes in the order of city blocks.
