Luigi Donatello Asero said:
I mean a line without spaces something like the lines on the page
http://www.cilea.it/WWW-map/NIR-map.html
The lines are part of the image. You use an image processing program to
add text and lines into an image.
(It would be possible, with the usual caveats, to create horizontal and
vertical lines using CSS and position them on the image. But that would
be unreliable and very clumsy as compared with the simple use of image
processing software.)
Hopefully you will create something more sensible than the image map
on the page you mention. That particular image map suffers from several
problems. Luckily there are links to alternatives that contain the
information as lists of links. An image map should always be
accompanied with such a list, especially since popular browsers
effectively fail to implement client-side image maps when the image is
not available, i.e. they don't make the areas available with their alt
texts.
And in that particular image map, lack of alt texts is essential when
the image is displayed, too. In many parts the server density is so
high that it is impossible to say which square corresponds to which
city unless you know Italian geography well. Well, there's the status
line, where the URL might help. But it's a poor surrogate for an
appropriate alt text.