Interactive extended elevations

[Phil Underwood]

I'm currently working on yet more bells and whistles for chasm.
In this case, a slightly more intelligent extended elevation processor.

If I recall correctly, there was a discussion on this a while back; this
would be my implementation=20

A selectable starting point.
Process consequent legs from left to right.
Individual legs can be *breakable* and/or *reversed*
Specification of several continuous legs, which will be extended as a who=
le=20

e.g

Plan view, up page is North                             A
                                                        |
                                                        |
            D         /\              /\         /\     |
=09    |\       /  \            /  \       /  \    |
            | \     /    \          /    \     /    \   |
            |  \   /      \        /      \   /      \  |
            |   \_/        \      /        \_/        \ |
            |               \    /                     \|
            |                \  /                       B
            |                 \/
            |                  C
            |
            |
            E

AB and DE are sloping sharply upwards. BCD is a very wide passage, with
the survey bouncing off the walls.
A standard extended elevation would highly exagerate the length of BCD,
giving

E
 \
  \
   \
    \
     \=20
      \
       \                   Big gap (won't fit on screen)
        \___________________|   |_____________________________B
         D                  |   |   C                         \
                                                               \
                                                                \
                                                                 \
                                                                  \
                                                                   \
                                                                    \
                                                                     \
                                                                      A
                                                                         =
 =20
However, if the section BCD is viewed at 90 degrees to the line BD, (or
about 300 degrees off north) and  plotted correctly, a much more accurate
representation of the passage length is given. e.g

E
 \
  \
   \
    \
     \=20
      \
       \               C is actually "in front of the screen"
        \___________________________________________________B
         D               C                                  \
                                                             \
                                                              \
                                                               \
                                                                \
                                                                 \
                                                                  \
                                                                   \
                                                                    A


That wasn't very clear, was it? :(




If a loop contains no breakable legs, then it will be broken at a
junction, which is unspecified.

If a loop contains one *breakable* leg, then it is broken at that leg. If=
 it
contains more than one, it will be broken at one of them (unspecified).

On encountering a *reversed* leg, the direction of unfolding is reversed.

The graphics interface will allow selection of the starting point,
modification of the properties of legs(breakable/reversible), and display
of legs according to their properties (breakable & broken, not breakable
but broken anyway, reversed)

The specification of which legs are to be breakable or reversed is done
after processing (ie there would no added survex commands)

Having rambled on at length about this, does anyone have any better
ideas/improvements? Can anyone see any potential problems with this?

--=20
Phil Underwood <furbrain@furbrain.screaming.net>
Homepage: http://members.xoom.com/bighairyone/
"It's not what you've got, it's how you make it explode."