On Feb 20, 11:03 pm, "John Rowland"
wrote:
wrote:
On Feb 20, 2:40 pm, "John Rowland"
wrote:

I'd like bus shelters to bear accurate mathematically distorted
geographical maps, where, for instance, distance from the centre of
the map is proportional to the square root of the actual distance on
the ground, and any super-long routes have an arrow at the edge of
the map listing further destinations.

How do you handle the case where two bus routes share the same stretch
of road, diverge, and then rejoin at another point?

You either give them different colours, or you show them as separating and
converging like the Northern Line - whichever makes the map easier to
understand (which would depend on what else was going on in the map).

But then this would destroy the accurate mathematical distortion
property.

--
Abi

wrote:
On Feb 20, 11:03 pm, "John Rowland"
wrote:
wrote:
On Feb 20, 2:40 pm, "John Rowland"
wrote:

I'd like bus shelters to bear accurate mathematically distorted
geographical maps, where, for instance, distance from the centre of
the map is proportional to the square root of the actual distance
on the ground, and any super-long routes have an arrow at the edge
of the map listing further destinations.

How do you handle the case where two bus routes share the same
stretch of road, diverge, and then rejoin at another point?

You either give them different colours, or you show them as
separating and converging like the Northern Line - whichever makes
the map easier to understand (which would depend on what else was
going on in the map).

But then this would destroy the accurate mathematical distortion
property.

Even Ordnance Survey 1:50000 maps contain local distortions to cope with the
fact that roads are shown wider than they really are.

On Wed, 21 Feb 2007, John Rowland wrote:

wrote:
On Feb 20, 11:03 pm, "John Rowland"
wrote:
wrote:
On Feb 20, 2:40 pm, "John Rowland"
wrote:

I'd like bus shelters to bear accurate mathematically distorted
geographical maps, where, for instance, distance from the centre of
the map is proportional to the square root of the actual distance
on the ground, and any super-long routes have an arrow at the edge
of the map listing further destinations.

How do you handle the case where two bus routes share the same
stretch of road, diverge, and then rejoin at another point?

You either give them different colours, or you show them as
separating and converging like the Northern Line - whichever makes
the map easier to understand (which would depend on what else was
going on in the map).

But then this would destroy the accurate mathematical distortion
property.

Even Ordnance Survey 1:50000 maps contain local distortions to cope with the
fact that roads are shown wider than they really are.

As does the A-Z - i cycled from Kilburn to Finsbury Park last night, along
a route i've never used before, with only the A-Z-derived London Cycle
Guide for company, and came across a number of junctions where the map
indicated i should be able to go straight over but actually had to make a
substantial dogleg, or turn down one road before i could turn onto the one
i wanted, etc.

tom

--
A complex system that works is invariably found to have evolved from a
simple system that worked. -- Gall's Law