I am forced to work in two locations, a local xy grid and a UTM location. I've worked out a simple appropriate transformation (rotation and displacement) to get vectors in the xy location into the UTM location, and vice versa. But there isn't an equivalent for rasters. Is there an easy way to reproject rasters from UTM into an arbitrary but known xy location? Many thanks,
Nick Cahill
On 08/05/12 19:28, Nick Cahill wrote:
I am forced to work in two locations, a local xy grid and a UTM
location. I've worked out a simple appropriate transformation
(rotation and displacement) to get vectors in the xy location into
the UTM location, and vice versa. But there isn't an equivalent for
rasters. Is there an easy way to reproject rasters from UTM into an
arbitrary but known xy location? Many thanks,
Using your transformation equation, you could translate the edges of a raster map to your new system and then use r.region.
Moritz
Dear Moritz and all,
Thank you for your suggestion; this is possible, but now I wonder if there's a more general solution. With those transformation parameters, could I define the placement of my xy location, and then use r.proj and similar tools to do the transformations of both raster and vectors between the two locations? It would make my life a whole lot easier.
Many thanks,
Nick
On May 9, 2012, at 4:32 AM, Moritz Lennert wrote:
On 08/05/12 19:28, Nick Cahill wrote:
I am forced to work in two locations, a local xy grid and a UTM
location. I've worked out a simple appropriate transformation
(rotation and displacement) to get vectors in the xy location into
the UTM location, and vice versa. But there isn't an equivalent for
rasters. Is there an easy way to reproject rasters from UTM into an
arbitrary but known xy location? Many thanks,Using your transformation equation, you could translate the edges of a raster map to your new system and then use r.region.
Moritz
Nick wrote:
Thank you for your suggestion; this is possible, but now I
wonder if there's a more general solution. With those
transformation parameters, could I define the placement of
my xy location, and then use r.proj and similar tools to do
the transformations of both raster and vectors between the
two locations? It would make my life a whole lot easier.
You might try the venerable i.vpoints in an xmon, then i.rectify.
The control POINTS file that that prepares (for the imagery group)
is essentially the same as what g.transform does for the wxGUI
georectification tool. The nice thing about i.vpoints is that
you can back-project an overlay of a vector map from the target
(to) location from within the source (from) location.
it can be a bit crunchy, but it works well.
(only available on MS Windows via cygwin)
Hamish