Re: [R-sig-Geo] polygon to raster -"adjusted" method

2012-11-02 Thread Robert Pazur
Dear Robert, thanks a lot for your answer. It helped me much. I used your suggested random sampling approach also for the rasterization of shapefile dataset. My results, however, seems strange (according to the patches proportion) compare to for example the standard max assignment method. Im posti

Re: [R-sig-Geo] readGDAL loses datum

2012-11-02 Thread Roger Bivand
On Fri, 2 Nov 2012, Oliver Soong wrote: I agree it seems to be happening when converting WKT to Proj4. However, is this more of a GDAL bug? system(paste("gdalinfo -proj4", img1.file)) [...] PROJ.4 string is: '+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +t

Re: [R-sig-Geo] readGDAL loses datum

2012-11-02 Thread Oliver Soong
I agree it seems to be happening when converting WKT to Proj4. However, is this more of a GDAL bug? > system(paste("gdalinfo -proj4", img1.file)) [...] PROJ.4 string is: '+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs ' I

Re: [R-sig-Geo] searching a Delaunay triangulation for nearest neighbor

2012-11-02 Thread Barry Rowlingson
On Fri, Nov 2, 2012 at 6:39 PM, CARTIER, ADRIAN AW (AG/1000) wrote: > All, > > I am looking for a solution to search a triangulation for the point closest > to a centroid of a collection of polygons. MATLAB has functionality called > dsearch. I was wondering if there was a similar. > > Here is t

[R-sig-Geo] searching a Delaunay triangulation for nearest neighbor

2012-11-02 Thread CARTIER, ADRIAN AW (AG/1000)
All, I am looking for a solution to search a triangulation for the point closest to a centroid of a collection of polygons. MATLAB has functionality called dsearch. I was wondering if there was a similar. Here is the set up vector xcoord of x-coordinates, ycoord of y coordinates, Tri, the Dela

[R-sig-Geo] raster package - zonal - standard deviations

2012-11-02 Thread Christian Levers
Hello, I am using the raster package to calculate zonal statistics for my stack of ca. 50 rasters (each raster is about 33 mio. pixels) and I am wondering if there is a simple way to calculate standard deviations for the zones since "sd" is not implemented in the presets for the "stat" argume

[R-sig-Geo] Kriging of values distributed on line

2012-11-02 Thread zbynek.jano...@centrum.cz
Hello, perhaps I am asking for something obvious, but I would like to perform interpolation of values, which are distributed on the line. my dataset consists of two vectors: stationing (distance from origin) and values. I would like to krige the values to obtain smooothed curve with variance estim

Re: [R-sig-Geo] spatial regression model

2012-11-02 Thread Paolo Piras
Dear Zia and all those that answered me, thankyou very much for your advices; I will surely include them in my analyses thankyou again paolo Da: Zia Ahmed [z...@cornell.edu] Inviato: giovedì 1 novembre 2012 14.58 A: Arnaud Mosnier Cc: Paolo Piras; r-sig-geo

Re: [R-sig-Geo] Question about space-time analysis routines

2012-11-02 Thread Nagle, Nicholas
Corey, You might also look at Simon Wood's mgcv package. It is a general purpose Generalized Additive Model package. There is a way to specify a Conditional Autoregressive Model in space. And you can interact this with temporal autocorrelation (or equivalently, with temporal splines). And,

Re: [R-sig-Geo] Question about space-time analysis routines

2012-11-02 Thread Corey Sparks
Thanks Edzer, The latter was really what I was looking for, specifically the spatio-temporal SAR models you describe. I assume that in order to generate the weights, you take the traditional neighbor lists generated by: nbs<-poly2nb(shapefile) and modify them to incorporate time as well? Best, C

Re: [R-sig-Geo] readGDAL loses datum

2012-11-02 Thread Roger Bivand
On Fri, 2 Nov 2012, Oliver Soong wrote: R 2.15.1 32-bit, rgdal 0.7.20, Windows 7. grid <- GridTopology(c(-210, 120), c(100, 100), c(1, 1)) p4s <- CRS("+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80 +towgs84=0,0,0") img1 <

Re: [R-sig-Geo] Question about space-time analysis routines

2012-11-02 Thread Edzer Pebesma
Corey, we've reported some work on ST geostatistics in: http://cran.r-project.org/web/packages/sp/vignettes/st.pdf and air quality interpolations in http://acm.eionet.europa.eu/reports/ETCACM_TP_2011_10_spatio-temp_AQinterpolation which has data and scripts in http://ifgi.uni-muenster.de/~b_grae

[R-sig-Geo] countingweights?

2012-11-02 Thread Adrian.Baddeley
salma anwar writes: > Hi, I am trying to fit a "Area-Interaction" point process model > to my data consisting of log-landing locations in a forest. > I get the following warning message along with the result of > the fitting: > "1: In countingweights(id, areas) : Some tiles with zero area

[R-sig-Geo] readGDAL loses datum

2012-11-02 Thread Oliver Soong
R 2.15.1 32-bit, rgdal 0.7.20, Windows 7. grid <- GridTopology(c(-210, 120), c(100, 100), c(1, 1)) p4s <- CRS("+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80 +towgs84=0,0,0") img1 <- SpatialGridDataFrame(grid, data.frame(ban

Re: [R-sig-Geo] countingweights?

2012-11-02 Thread Rolf Turner
On 01/11/12 18:22, salma anwar wrote: Hi, I am trying to fit a "Area-Interaction" point process model to my data consisting of log-landing locations in a forest. I get the following warning message alongwith the result of the fitting: "1: In countingweights(id, areas) : Some tiles with zer