Hi, Have a look at the overlay() function in the sp-package.
cheers, Paul Yong Li wrote: > Hi ALL, > > I want to pick up cells values of a grid (say a RS image) using points' > positions. For example, I have an image and a point shape file with the same > coordinate system, then I try to overlay points on the image, and want to get > the cell values of the on-point cell and 8 surrounding cells. Could any > expert give some tips to solve my problem? > > Regards > > Yong > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL > PROTECTED] > Sent: 2008年12月3日 22:00 > To: [email protected] > Subject: R-sig-Geo Digest, Vol 64, Issue 3 > > Send R-sig-Geo mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > or, via email, send a message with subject or body 'help' to > [EMAIL PROTECTED] > > You can reach the person managing the list at > [EMAIL PROTECTED] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of R-sig-Geo digest..." > > > Today's Topics: > > 1. GSTAT: Optimize power value for IDW (Zev Ross) > 2. Re: GSTAT: Optimize power value for IDW (Paul Hiemstra) > 3. R: GSTAT: Optimize power value for IDW (Paul Hiemstra > approach) (Alessandro) > 4. Re: R: GSTAT: Optimize power value for IDW (Paul Hiemstra > approach) (Zev Ross) > 5. Re: R: GSTAT: Optimize power value for IDW (Paul Hiemstra > approach) (Edzer Pebesma) > 6. Raster file from ascii file and flattening Africa .... :) > (Corrado) > 7. Re: Raster file from ascii file and flattening Africa ....:) > (Kamran Safi) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 02 Dec 2008 13:59:47 -0500 > From: Zev Ross <[EMAIL PROTECTED]> > Subject: [R-sig-Geo] GSTAT: Optimize power value for IDW > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi All, > > ArcGIS has a nice little button that calculates the optimal power value > to use for inverse distance weighting based on cross-validation and > RMSPE. Just wondering if anyone had written something similar in R -- > I'm using GSTAT and I'd like to avoid back and forth with ArcGIS (and > obviously I'd like to avoid writing it myself as well!). > > Zev > > -- Drs. Paul Hiemstra Department of Physical Geography Faculty of Geosciences University of Utrecht Heidelberglaan 2 P.O. Box 80.115 3508 TC Utrecht Phone: +31302535773 Fax: +31302531145 http://intamap.geo.uu.nl/~paul _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
