### astTimeMap

Create a TimeMap

#### Description:

This function creates a new TimeMap and optionally initialises its attributes.

A TimeMap is a specialised form of 1-dimensional Mapping which can be used to represent a sequence of conversions between standard time coordinate systems.

When a TimeMap is first created, it simply performs a unit (null) Mapping. Using the astTimeAdd function, a series of coordinate conversion steps may then be added. This allows multi-step conversions between a variety of time coordinate systems to be assembled out of a set of building blocks.

For details of the individual coordinate conversions available, see the description of the astTimeAdd function.

#### Synopsis

AstTimeMap $\ast$astTimeMap( int flags, const char $\ast$options, ... )

#### Parameters:

##### flags
This parameter is reserved for future use and should currently always be set to zero.
##### options
Pointer to a null-terminated string containing an optional comma-separated list of attribute assignments to be used for initialising the new TimeMap. The syntax used is identical to that for the astSet function and may include " printf" format specifiers identified by " %" symbols in the normal way. If no initialisation is required, a zero-length string may be supplied.
##### ...
If the " options" string contains " %" format specifiers, then an optional list of additional arguments may follow it in order to supply values to be substituted for these specifiers. The rules for supplying these are identical to those for the astSet function (and for the C " printf" function).

#### Returned Value

##### astTimeMap()
A pointer to the new TimeMap.

#### Notes:

• The nature and units of the coordinate values supplied for the first input (i.e. the time input) of a TimeMap must be appropriate to the first conversion step applied by the TimeMap. For instance, if the first conversion step is " MJDTOBEP" (Modified Julian Date to Besselian epoch) then the coordinate values for the first input should be date in units of days. Similarly, the nature and units of the coordinate values returned by a TimeMap will be determined by the last conversion step applied by the TimeMap.

• A null Object pointer (AST__NULL) will be returned if this function is invoked with the AST error status set, or if it should fail for any reason.