[Koha] moving to Koha from an older system.

[Gavin McCullagh]

Hi,

I'd like if possible to solicit a little advice for a group in Dublin who
I'm assisting with a move to Koha.

They can export UKMarc and USMarc from their existing system, but not
Marc21.  As far as we can tell Marc21 is the system which Koha defaults to.
The old systems all place stuff like the copy data under different tag
numbers so this doesn't work entirely as is.  

It seems like we can remap Koha's Marc tag stuff to suit our needs.
Alternatively, we can convert Marc->XML, make changes to the XML and
convert back again.

My experience, such as it is, is that with software like this one is best
being in the long term sticking as close to the defaults as possible.  For
this reason, I'm leaning toward doing the conversion up to Marc21 once and
for all.  As I see it, their Marc data will then be in an up-to-date
standard format.

I had a look at XML::Simple last night which, although rather slow on a
large Marc file, does seem to be a fairly straightforward way of
arbitrarily remapping the XML file automatically.  I am happy to post the
script if I get it working.

So, am I nuts to even try this?  Should we just remap things in Koha?  Is
there a third, better way to do this?

Gavin