[Therion] Automatic declination correction by date to Eastings and Northings different to survex

[Andrew Atkinson]

I have a few files that are fake data made from paper surveys. These 
come in various formats but a common one, and the one I tend to make if 
I do it is in the form of

data cartesian station easting northing altitude

It appears that Therion applies automatic declination by date to this 
form of data, so it defaulting to cartesian magnetic
This is not the same default as Survex

"By default, the North used is True North, but you can specify to use 
Magnetic or Grid North (in the input coordinate system) with the 
*cartesian command, and also specify an additional rotation to apply "

The cartesian command does not seem to work in Therion. For now I've 
bodged it buy applying declination 0 degrees but it would be better if 
Therion followed the Survex manual to which the Therion book refers to 
for commands.

An example file is

http://www.cave-registry.org.uk/svn/CheddarCatchment/Longwood/Renolds/Renolds.th
  You will need revision 479, otherwise you will get the bodge fix

thanks

Andrew