[GRASSLIST:198] rotation

[David Strauch]

Hello all,

I wrote last week asking if there wasn't a way to rotate maps in grass, 
partly as a way to save processing time.  I'd like to thank those who 
responded, who have given me much to think about.

Masking seems like an excellent way to reduce the computation time.  
Can it be used for vectors as well as rasters?

I still work primarily with vectors, perhaps because I initially 
started doing GIS work in the ArcInfo environment.  They have seemed 
intuitively more elegant and efficient to me (and more independent of 
scale, as someone pointed out), but I have lately been starting to 
question this prejudice...

If I shift to rasters I may try David Finlayson's rotation script or 
Morten Hulden's solution of exporting, rotating and reimporting into a 
new location (I'm assuming this could be done somehow without losing 
attributes).  Or it may be that vector endpoints could be converted to 
sites and rotated, converted back to vector endpoints and rebuilt into 
vectors.

But I'm still importing various coverages and it seems potentially 
cumbersome to do this process for each one -- especially if I later 
want to readjust the orientation.  I suppose I was hoping that I could 
create new locations that had different orientations, and be able to 
reproject coverages (including vectors) into these locations.  It would 
be nice to do this while working (ie with geo-referencing available), 
but it looks like (the way regions are defined) at this point map 
rotation will have to wait until I'm ready to print stuff out.

Again, thanks all,
David