Help - my cave is inside-out

[Wookey]

+++ Martin Budaj [05-01-03 12:59 +0100]:

>> There is another problem. Even if scrap boundary has correctly specified
>> all -outline out/in/none options, there may be problem to determine which
>> area is inside of the scrap if the outline crosses itself (like figure 8).
>> In such a case you get a MetaPost warning
>>
>> Warning: scrap outline intersects itself in bmb3_s3 at fake


OK. I have another big section of cave that is currently broken due to
mysterious therion metapost errors. I've tried to track it down but I don't
understand well enough to do it.

I am getting this error:
 ! angle(0,0) is taken as zero.
 l_arrow->...d(angle(direction.infinity.of(EXPR0))-
 90)shifted(point.infinity....l.5565 ),2);

 The angle' between two identical points is undefined.
 I'm zeroing this one. Proceed, with fingers crossed.

I assume this means that I have two points on top of each other - but I
don't know in which scrap, or which line, so it is not practical to find it.

The offending files are at:
http://trilogy-gw.aleph1.co.uk/~wookey/files/soundriver.tgz
http://trilogy-gw.aleph1.co.uk/~wookey/files/soundriverpic.tgz (includes
scans)

It seems that if I include any of soundriver2_s1 soundriver3_s1 or
soundrivercrab_s1 then it breaks. soundriver2_s1 is particularly perplexing
as it is a straight bit of passage with no areas in it, 3 stations, and not
much detail - seems to me there is very little to go wrong.

I did have soundriver3_s1 working last night I thought, but not now...

I am afraid I am going to keep sending you these until we work out some
better debugging system  :-(  or I get a lot smarter.

Wookey
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