[postgis-users] Make a shorter line from a given line

[Daniel Grum]

Hy,

I want to make a new line from a given line -->both geometry types are 
MULTININESTRING

Every step the new line should be "x meters" shorter than the original.

I get the length of the line, f.e. 5000 meters (length(the_geom)) and 
after the step the new Line should be only 4000 meters.

I have a idea but it isn't ready:

UPDATE table
SET the_geom = (SELECT MakeLine(StartPoint(line.the_geom), 
EndPoint(line_merge(line.the_geom)))
                            FROM public.table line
                            ORDER BY line.gid);

But in if I do so I have no chance to say that the new line has to be 
100meters shorter than the original line.

Are there any ideas how I can solve this problem?

Thanks,
--Daniel