mtrack Specifications: Version 2.3

mtrack Specifications, Version 2.3: Notes

This example and the next are only heuristic, as the series in question lacks the metadata information that would be required for mapping.
Of the 515 series currently ( 6 Jun 2020) in namespace hmi, 283 have the keyword CADENCE, while only 257 have the keyword T_REC_step.
Of the 238 series in namespace mdi, 67 have the keyword CADENCE and 72 have the keyword T_REC_step.
Of the 117 series in namespace aia, 31 have the keyword T_REC_step and 3 have the keyword CADENCE. Specifically:
In namespace aia, there are six time-like prime keys in various series (none has more than one):
```
  DAY		 2
  OBS_DATE	 1
  PACKET_TIME	43
  T_OBS		10
  T_REC		31
  T_START	 3
```
There are 3 series that have a CADENCE key, but all are variable in scope and would be ignored in favor of the corresponding prime-key step
In namespace hmi, there are six time-like prime keys in various series (none has more than one):
```
  DAY		  7
  MidTime	  4
  OBS_DATE	  1
  PACKET_TIME	 66
  T_REC		257
  T_START	 62
```
There are 35 series with a variable scope CADENCE key that would be ignored in favor of the prime key step value. There are 31 series with CADENCE keys but no time-like prime keys; none contain trackable solar imagery. There are no series for which the CADENCE key value which would be used differs from the prime key step value
In namespace mdi, there is one time_like prime key, T_REC, in 72 series. There are seven series with a variable scope CADENCE key that would be ignored in favor of the T_REC_step value. There are eleven series with CADENCE keys but no time-like prime keys; none contain solar imagery that could be used for tracking. There are eight series for which the constant CADENCE key value (which would be used) differs from the T_REC_step value:
```
  mdi.fd_Ic_06h :	T_REC_step = 21600	Cadence = 60
  mdi.fd_M_extract :	T_REC_step = 60		Cadence = 1
  mdi.fd_M_lev182 :	T_REC_step = 60.0	Cadence = 1.0
  mdi.fd_ic_06h_mod :	T_REC_step = 21600	Cadence = 60
  mdi.hr_M :		T_REC_step = 60		Cadence = 1
  mdi.hr_M_bin2x2 :	T_REC_step = 60		Cadence = 1
  mdi.hr_M_mod :	T_REC_step = 60		Cadence = 1
  mdi.limb_figure :	T_REC_step = 720	Cadence = 60
```
Note that five of these clearly result from a failure to take the keyword unit into account, assuming that the CADENCE key unit is "s", when in fact it is "Minutes".