Information Technology Reference
In-Depth Information
Consider now another text file (“table.txt”) which, as a simple “.txt” file is easily
readable on a PC - again the “.txt” usually lets us guess, correctly in this case, that
this is an ASCII encoded file.
In this case we are more obviously in some trouble because although we can see
something which we can reasonably assume are numbers, we do not know what the
numbers mean.
If we are told that the numbers under the headings “X”, “Y” and “Z” provide
us with the sides of a rectangular cuboid, then we can calculate the volume of that
shape using the formula “X
∗
Y
∗
Z” for each row, namely 14.742. 31.8 and 114.034.
On the other hand we might be told that “X” is the longitude on Earth, “Y” the
latitude, both measured in degrees and “Z” is the concentration of a certain chemical
in parts per billion.
We see that the format alone is insufficient; one needs to know what
the contents (e.g. the numbers) mean.
By Non-Rendered Digital Object we mean things which, like table.txt, are not
simply rendered but rather are to be processed to produce any number of pos-
sible outputs. For example table.txt could be plotted, displayed as a pie-chart or
histogram. Alternatively the information in the columns of table.txt could be used
to calculate the density of chlorophyll in the Amazon rain forest (if that is the sort
of information there is in table.txt).
As another example one can take a digital object from the GOME instrument
[
21
], which might be as shown in Figs.
4.5
,
4.6
, and
4.7
.
Fig. 4.5
GOME data -
binary
Fig. 4.6
GOME data - as
numbers/characters
