> I am looking for a method to extract roads automatically
> in remote sensed imagery such as Landsat TM or SPOT.
> Does anyone have idea of a sophisticated approach to the problem ?
> Information on previous works or publications would help me very
> much.
>
It's just like carving an elephant: start with a block of wood, and take
away everything that doesn't look like an elephant.Although I'm not the epitome of an imagery whiz, I seem to recall that
even SPOT data gives you an awful lot of trouble finding classifications
that hold still for the kind of linear features you're looking for.
The usual approach is to use n edge detection algorithm. Of course
this is gonna detect a lot of edges you don't wanr, and of course, miss
a lot of edges you DO want due to tree cover/shadow or whatever etc. etc.
It's pretty much a none starter to try and do this.
An alternative would
be to use the imagery as a back drop cell display in v.digit in GRASS and
use the mouse to quickly digitize along the roads on-screen....no map
reg. hassles, and your extracting the roads off the image, albeit manually.
Note: you've obviously got to rectify/register the imagery first!!
Marcus Tooze
USACERL-TAC
Disclaimers etc etc.