Geoscience Reference
In-Depth Information
spaced. h e hardness scale of German mineralogist Friedrich Mohs
(1773-1839) is one example of an ordinal scale. h e hardness value
indicates the material's resistance to scratching. Diamond has a hardness
of 10, whereas the value for talc is 1, but in terms of absolute hardness
diamond (hardness 10) is four times harder than corundum (hardness
9) and six times harder than topaz (hardness 8). h e Modii ed Mercalli
Scale, which attempts to categorize the ef ects of earthquakes, is another
example of an ordinal scale; it ranks earthquakes from intensity I (barely
felt) to XII (total destruction) (Richter 1958).
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ratio data
- h ese data are characterized by a constant length of successive
intervals, therefore of ering a great advantage over ordinal data. h e zero
point is the natural termination of the data scale, and this type of data
allows for either discrete or continuous data sampling. Examples of such
data sets include length or weight data.
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interval data
- h ese are ordered data that have a constant length of
successive intervals, but in which the data scale is not terminated by
zero. Temperatures C and F represent an example of this data type even
though arbitrary zero points exist for both scales. h is type of data may be
sampled continuously or in discrete intervals.
In addition to these standard data types, earth scientists frequently encounter
special kinds of data such as
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closed data
- h ese data are expressed as proportions and add up to a i xed
total such as 100 percent. Compositional data represent the majority of
closed data, such as element compositions of rock samples.
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spatial data
- h ese are collected in a 2D or 3D study area. h e spatial
distribution of a certain fossil species, the spatial variation in thickness
of a sandstone bed and the distribution of tracer concentrations in
groundwater are examples of this type of data, which is likely to be the
most important data type in earth sciences.
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directional data
- h ese data are expressed in angles. Examples include
the strike and dip of bedding, the orientation of elongated fossils or the
l ow direction of lava. h is is another very common type of data in earth
sciences.
