[GRASSLIST:16] Re: d.zoom - I wonder why

[Glynn Clements]

John Doucette wrote:

> I wonder why sometime d.zoom works one way then again it acts another.
> Sometimes I can zoom on vector only displays. Other times Grass insists that
> it wants to have an open raster.  Last night I was trying to some on some
> sites on a display.  Grass insisted it wanted a raster.  I don't have any
> rasters for that map set.

d.zoom first checks whether there are any raster, vector or sites maps
currently displayed; if there aren't, the "rast=" option becomes
mandatory.

However, it's conceivable that some program might display a map but
fail to record the fact that it's displayed it; in which case, d.zoom
will behave as if the map isn't there (i.e. require the "rast="
option).

AFAICT, d.zoom really needs to be re-written from scratch; actually,
it should probably be two different programs: one which zooms specific
maps, and one which zooms whatever happens to be on the display.

-- 
Glynn Clements <glynn.clements at virgin.net>