>Now I have added this into my surveys, I see that the centreline is

rendered as solid lines when you include the centreline (and have not

set the centreline symbol group to be hidden), but if you do not

include the centreline then the survey lines renderer in the scraps

are just dashes at each station rather than complete lines running the

complete distance between pairs of stations. Not a problem, but

curious as to why I get two different styles for cave survey lines.

      It has always been this way.  I did delve into the metapost once to see why, from a code perspective.  It seems rational behaviour as far as 'using it' goes.

>Then I tried this on my 66km system survey and with centrelines set to

show in my layout, I found metapost used up all the words of memory it

is allowed so I get no output. From my logfile:

...

How can I get around this limitation?

      Interesting.  I have never come across this limitation, although metapost usually logs messages of seeming complaint.  I inquired on the forum years ago, and one of the Martin's or Stacho assured me that it should never actually run out.  Not sure if I have ever plotted 66km of centreline? I have probably come close.

>I can see how it is useful to be able to render centrelines and stations for the entire system regardless.

      Yes, very useful.  I add each survey as it becomes available.  It is then in the outputs as a reminder to draw the scraps!  Further - you can differentiate the flags that apply to each survey shot with colour and line style.

See the wiki http://therion.speleo.sk/wiki/doku.php/metapost#general_symbol_examples

Under the heading “Visualize cave centreline shot flags with colour for splay and duplicate, and dash for approximate shot flags”

Bruce