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Maximum and Mininum Values in Table Columns
HEASARC uses the following keywords to specify the limits on data in a
table column. They are analogous to the DATAMAX and
DATAMIN keywords used for arrays.
For example, if the third column in a table of positions was declination,
then the following keywords might be present.
TTYPE3 = 'DEC '
TFORM3 = '1E '
TUNIT3 = 'DEGREES '
TLMAX3 = 90.00
TLMIN3 = -90.00
TDMAX3 = 46.00
TDMIN3 = -63.10
HEASARC also recommends the following restrictions when these
keywords are used:
- The data type of the keyword value should be the same as that of
the data in the column it describes.
- The keywords are to refer to all elements of a vector column
- As with DATAMAX and DATAMIN, the keywords apply to
the values after any scaling prescribed by the values of the
TZERO and TSCAL keywords has been applied.
- Values of TDMIN less than those of TLMIN and
values of TDMAX greater than those of TLMAX
are permissible; the meaning is not defined in this convention.
- If the value of the keyword for the maximum is less than that of the
value of that for the minimum, then the values are taken to be
undefined.
Next: World Coordinates in Tables
Up: HEASARC
Previous: Proposed TSORTKEY Convention
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William Pence
2004-01-07