As far as I can discover, there isn't any such thing as a tactile map of Brighton and/or Hove to assist blind people, not even of Brighton city centre.

Well, of course there isn't, because looking at a visual map and using a raised-line one by touch are utterly different processes.

You can't just whip a tactile map out of your pocket or handbag, unfold it in the street and feel about for the appropriate cartographic detail to help you on your way.

For a start, a tactile map would just be too big. They have to be on a much larger scale.

At ordinary inkprint scales, they'd be altogether too confusing for even the most discerning hands.

By even just glancing at an inkprint map you get vastly more usable information than you would by placing your hands on a tactile equivalent.

Reading such a map is a process of building up your mental picture of its contents as you move your hands to make sense of its directions, connections and intersections.

Indeed, assistance from someone sighted may well prove essential - at least to get started.

It's much more a matter of private study. But while tactile maps can never really compare with the usefulness of inkprint, they can most definitely be of value to blind people.

Which is pretty much the conclusion arrived at following an experiment a few years ago to install distinctively-coloured (for the benefit of partially-sighted people also) tactile maps of major bus routes at some bus stops.

No one could agree how the 3ft by 4ft maps should be placed, for widest ease of reference.

The general verdict, though, was it was good that blind and partially-sighted bus users' needs were being considered.

And so they still are, I'm reliably informed.

But this time, something more on the lines of the Royal National Institute for the Blind's book format maps will be the result.

These are made in response to individuals' requests.

So why has no one yet requested a Brighton and Hove map?

Possibly because the service isn't well known.

And because most blind people, I believe, won't ever have had the opportunity to find out how useful a tactile map could be to them.

Then why haven't I put in a request for one, if I'm so bothered?

Good question.

I've been meaning to but I've been dithering over how much I'd want included.

But I've also an idea for a different sort of "map" (or, rather, a series of them) that might prove useful.

This would be a collection of audio recordings, each covering a single, major shopping street.

Starting by giving its general orientation and location, then the shops and other buildings along each side, in a given direction, would be named and their merchandise or function briefly described.

Interspersed with this would be the names of any tributary streets, together with descriptions of their crossings. The positions of bus stops, with route numbers, would be mentioned.

Even as one side of the street is being described, it would also be useful to know about streets leading off from the opposite side and any major shops or other buildings.

The big drawback to such a scheme, of course, is how quickly changes happen.

Master recordings would have to be in a readily-editable format, such as Minidisc. Members of the public could then request up-to-date cassettes (or other format) copies for the streets of their choice.

This isn't written in stone.

So, if this piece makes it on to the local talking newspaper for blind people, I'd be interested to learn what people think.