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When FITS was originally developed, there was no
standard format for the internal representation of floating point data. Only integer
formats were allowed in the data array. The scaling scheme using the keywords
BZERO and BSCALE was devised in order to make it possible to
represent inherently floating point physical values using a data array of integers.
The physical value of the data represented by an array member would be derived
from equation 3.2. While scaling is no
longer required to represent floating point numbers, it remains a useful tool.
Representation of unsigned integer quantities is one application.
Be careful when attempting to scale data sets with large dynamic
range. If one converts such data to integers and then tries to convert
back to floating point, so much precision may be lost that the
original data values will be irretrievable.