The features described in this topic are obsolete
and should not be used in new IDL code.

READ_TIFF

The following keywords to the READ_TIFF function are obsolete.

Keywords

ORDER

Set this keyword to a named variable that will contain the order value from the TIFF file. This value is returned as 0 for images written bottom to top, and 1 for images written top to bottom. If an order value does not appear in the TIFF file, an order of 1 is returned.

The ORDER keyword can return any of the following additional values (depending on the source of the TIFF file):

Table 4-1: Values for the ORDER keyword
Rows	Columns
1	top to bottom, left to right
2	top to bottom, right to left
3	bottom to top, right to left
4	bottom to top, left to right
5	top to bottom, left to right
6	top to bottom, right to left
7	bottom to top, right to left
8	bottom to top, left to right

Reference: Aldus TIFF 6.0 spec (TIFF version 42).

UNSIGNED

This keyword is now obsolete because older versions of IDL did not support the unsigned 16-bit integer data type. Set this keyword to return TIFF files containing unsigned 16-bit integers as signed 32-bit longword arrays. If not set, return an unsigned 16-bit integer for these files. This keyword has no effect if the input file does not contain 16-bit integers.