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

[Jarek Jasiewicz]

Moritz Lennert wrote:
> On 20/03/08 11:17, Jarosław Jasiewicz wrote:
>> 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
>
> Either ressample your rasters to coarser resolution to make them 
> coincide, or convert to vector and use a combination of v.patch + 
> v.clean (e.g. v.clean input=lines1 output=lines2 err=points tool=break)
>
> Moritz
thanks for ansfer
I tried it with similar way (v.patch +v.clean + topology report) but it 
is not it. I need EXACT coordinates of pixels on intersection do to 
transfer it to another program
I soleved problem with r.to.vect and detailed corecting line manualy on 
problematic areas, little more work but result as I expected.
Jarek