Re: [R] confine a dataframe with a polygon

From: temiz <temiz_at_deprem.gov.tr>
Date: Wed 04 Apr 2007 - 12:36:12 GMT

Roger Bivand wrote:
> On Tue, 3 Apr 2007, temiz wrote:
>
>
>> hello
>>
>> how can I confine a dataframe with a known polygon that is part of whole
>> data ?
>>
>
> Could I suggest following up this question on the R-sig-geo list? It is
> not clear what you want to do - are the rows in the data frame points
> which may lie inside or outside a polygon? If so, the overlay() methods in
> the sp package may be suitable.
>
>
>> regards
>>
>>
>>
>
>
thank you for your reply

I have not been aware of that list (R-sig-geo list) My data is elevation point data in a text file. I want to create DEMs with different interpolation methods for comparision.
Actually I created DEM in GRASS using spline tension. Then I want to create DEM in R with different techniques to compare. But my data seems so huge for GSTAT-kriging and FIELDS-krig. So I decided to select smaller interpolation area within whole data.

How can I define a subregion in which I do interpolation ?

I found locator and chull function that may serve this.

I will regard your recommendations.

PS : Thinking facing a memory problem, I refrained from GRASS-R interface.

-- 
Ahmet Temiz


-- 
This message has been scanned for viruses and\ dangerous con...{{dropped}}

______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Received on Wed Apr 04 16:39:27 2007

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.1.8, at Wed 04 Apr 2007 - 07:30:54 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.