[R-sig-Geo] Creating a Grid out of a matrix of coordinates

[Paul Hiemstra]

Hi,

Then your points are not a grid perfectly. Read the docs for gridded, 
specifically the tolerance argument.

cheers,
Paul

Mehdi Khan schreef:
> Hello Paul,
>
> I get the following error: 
>  gridded(wald)= TRUE
> suggested tolerance minimum: 0.125000000000666
> Error in points2grid(points, tolerance, round, fuzz.tol) :
>   dimension 1 : coordinate intervals are not constant
>
> What do I do?  Thanks a lot!
>
> On Fri, Aug 21, 2009 at 12:34 PM, Paul Hiemstra <p.hiemstra at geo.uu.nl 
> <mailto:p.hiemstra at geo.uu.nl>> wrote:
>
>     Hi,
>
>     If your object's points are regularly spaced and in a
>     SpatialPoints object, use:
>
>     gridded(myobj) = TRUE
>
>     Or you can from a data.frame with the coordinates and attributes
>     to a grid by:
>
>     coordinates(myobj) = ~x+y
>     gridded(myobj) = TRUE
>
>     or shorthand:
>
>     gridded(myobj) = ~x+y
>
>     cheers,
>     Paul
>
>     Mehdi Khan schreef:
>
>         Hello, I have a matrix 1.5 million rows long..
>
>         wald:
>
>          coordinates  V3
>         1  (-124.996, 42.0458) 150
>         2  (-124.987, 42.0458) 150
>         3  (-124.979, 42.0458) 150
>         4  (-124.971, 42.0458) 150
>         5  (-124.963, 42.0458) 150
>         6  (-124.954, 42.0458) 150
>         7  (-124.946, 42.0458) 150
>         8  (-124.938, 42.0458) 150
>         9  (-124.929, 42.0458) 150
>         10 (-124.921, 42.0458) 150
>          
>
>         I would like to coerce this into a grid object so that I can
>         overlay points
>         onto it.  How exactly could I accomplish that?  Thank you!!
>
>         Mehdi Khan
>
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>
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