patching across utm zones

[Simon Cox]

Thanks Pat

Malcolm Williamson from U.ARK sent me a very smart way to do the trick
(should have thought of it myself!)

Here it is:


> Simon,
> These are some instructions that I wrote for some co-workers when we had to
> patch landuse/land cover maps across two zones. If you are interested I can
> send you the original Postscript document as well. Hope this helps.
>
> --------
>
> ALIGNMENT OF RASTER MAPS FROM DIFFERENT UTM ZONES
>
> 1.    Copy raster file [filename]that is in incorrect UTM zone to mapset in
> desired UTM zone.
>
> 2.    Use "i.group" to create a group [groupname] that includes [filename] of
> raster file that is in incorrect zone.
>
> 3.    Use "i.target" to identify [groupname] as target.
>
> 4.    Enter "i.points", identifying group as [groupname]. Display the raster
> map [filename] from the selected group. Use the Plot Raster command
> to display the raster map that you want to patch to in the upper right
> quadrant of the monitor.
>
> 5.    Use the mouse to mark four points in the raster map to be rectified.
Make
> the matching marks on the other map (upper right quad); the exact
> placement of the marks are of no consequence. Exit "i.points".
>
> 6.    Under the mapset "cd" to group/[groupname]. "cp" the file POINTS to
> [tempfile].
>
> 7.    "vi" [tempfile]. Edit out all information except for the eastings and
north-
> ings under the heading "image". The finished file needs to look as fol-
> lows:
>
>
>
>       >590101.351351  3984300.003718
>
>       >591300.900900  3873305.405405
>
>       >770502.477477  3987894.593593
>
>       >773695.495495  3876901.801801
>
>       >
>
>       >
>
>       >end
>
>
>
> 8.    Enter "m.u2ll spheroid=clark66 zone=[original zone of map] input=[-
> tempfile] output= [tempfile.ll]".
>
> 9.    Enter "m.ll2u spheroid=clark66 zone=[desired zone] input=[temp-
> file.ll] output= [tempfile.utm]".
>
> 10.   "lp [tempfile.utm]".
>
> 11.   "vi" the file POINTS, and edit the eastings and northings under
"target"
> to match the coordinates on the printout of [tempfile.utm].
>
> 12.   Run "i.rectify" on group [groupname], raster map [filename]. The output
> file should be called something like [filename.rect].
>
> 13.   Use "g.region" to directly modify the region so that it is large enough
to
> display both raster maps. "d.erase", and then display both maps.
>
>
> --
> Malcolm D. Williamson - Research Assistant       E-mail:
malcolm at cast.uark.edu
> Center for Advanced Spatial Technologies      Telephone: (501) 575-6159
> Ozark Rm. 12                                        Fax: (501) 575-3846
> University of Arkansas
> Fayetteville, AR 72701
>
----
__________________________________________________________________
				Dr Simon Cox
         __  L				
      ,~'  L_|\            	Department of Earth Sciences       
   ,-'         \         	Monash University    
   (            \		Clayton  Vic  3168  Australia
   \    ___     /	
    L,~'   "\_x/		Phone +61 3 565 5762
              u   		Fax   +61 3 565 5062
				simon at cerberus.earth.monash.edu.au
__________________________________________________________________