[GRASS-user] intersection of line-data and grid

[SGW00412 at nifty.com]

Hi all.

I am a beginner of grass-GIS.
I want to divide line data with a grid.
I want to find the length of line data divided by every grid afterwards.
Finally, I want to do a raster display of the length of line data every grid.

For example, river line with a grid.
For example, road line with a grid.
For example, bird migration route with a grid.

I succeeded by the import of line data.
I succeeded by the making of grid data.
However, I failed by the overlay analysis of line data and grid data.
The command function that I used is an overlay and select.

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v.overlay ainput=line-data atype=line alayer=1 binput=grid btype=area blayer=1 
output=length_grid operator=or olayer=1,0,0

v.select ainput=grid binput=line-data out=length_grid op=overlap
-----

Please teach me technique to perform this.
If it is FAQ, I apologize.

shimada from japan.