[R] Using GIS data in R

[Zuofeng Shang]

Many thanks Rolf! Your help is highly appreciated
since it helps me understand the clue of solving my problem.

Have a wonderful Sunday!
Jeff

于 2011/11/20 15:52, Rolf Turner 写道:
> On 21/11/11 10:19, Zuofeng Shang wrote:
>> Hi Rolf,
>>
>> Thanks very much for suggestions! Sorry if I made my question not very
>> clear.
>>
>> The context is as follows. I have a set of locations with coordinates
>> (latitude and longitude)
>> from Texas region. Some of the locations are within Texas while some
>> of them are not.
>> I am trying to find those locations within Texas by looking at if the
>> coordinate of each location
>> is within the boundary of Texas.
>>
>> Now I agree with you that the boundary of Texas is polygon although it
>> looks like "irregular".
>> I find your previous post very helpful. inside.owin() will do the job
>> but I have to figure out
>> the boundary (as a polygon) of Texas. Since I do not have the
>> shapefile of Texas, this will be
>> difficult for me. I am not sure if the shapefile of the US states are
>> available in R. If it not,
>> how can I get the shapefiles? Thanks a lot for kind help!
> This is not my area of expertise (if indeed I have such an area at all!
> :-) ) but
> I'm sure that maps of the states of the USA --- including Texas, even!
> --- are readily available
> from various sources.  I.e. from various GIS's or perhaps from the
> "maps" package.
>
> With a bit of luck someone on the list will chime in with something more
> specific.
>
> Or you could try asking "how/where can I get a shapefile specifying the
> boundary
> of Texas" on the R-Sig-Geo list.
>
> HTH
>
>       cheers,
>
>           Rolf


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