[R] a geographical factor

[Rolf Turner]

I'm too lazy to figure out the details of what you are trying to do, but 
I think it is possible that you might find the facilities of the 
spatstat package useful and that these might save you some 
wheel-reinvention.  Look in particular at the quadrats(), tess() and 
im() functions.

cheers,

Rolf Turner

On 01/03/14 13:40, Bill wrote:
> Hi. I have a dataframe called radSamp
>
> which looks like this:
>
>> head(radSamp[,c(3,4,5)])
>    Latitude Longitude Value
> 1 39.16094  140.4883    45
> 2 32.84428 -117.2240    47
> 3 35.80605  139.3789    28
> 4 35.07816 -106.6123    50
> 5 35.83174  136.2027    35
> 6 34.78944  137.9496    32
>
> This is radiation data from the area around Fukushima, Japan.
> I want to partition this region into about 40x40 rectangles. I think that
> if I can create a factor f consisting of these 1600 rectangles then I can
> focus on what is happening in each of these rectangles by
> using split(radSamp$Value, f).
> The area I want to focus on is defined by the following 4 corners of a
> rectangle:
>
> ~Akita
> Lat    = 39 degrees,   41.4 minutes   North
> Long = 137 degrees,   10.1 minutes   East
>
>
> East of Akita
> Lat    = 39 degrees,   41.4 minutes   North
> Long = 141 degrees,   57.5 minutes   East
>
> ~Toyama
> Lat    = 36 degrees,   42.2 minutes   North
> Long = 137 degrees,   10.1 minutes   East
>
> East of Toyama
> Lat    = 36 degrees,   42.2 minutes   North
> Long = 141 degrees,   57.5 minutes   East
>
> Can anyone suggest how to create such a factor?