[GRASS-user] How to find intersection of two lines

[Jarosław Jasiewicz]

Hi I have lots of raster, thinned lines and second raster with with one 
line. I must find all points where second line intersect with lines on 
first raster
it is very simple:
 
r.mapcalc points=if(raster_two==1&&raster_one==1,1,null())

but there is one exception:

AB
BA

when lines intersect with 45 grades. There is intersection but without 
common point. Naither buffor nor grow is not a solution because I need 
exactly one point lying exactly on line from raster one

Any Ideas