Re: [R-sig-Geo] coordinate system in ncdf4

2013-08-30 Thread Michael Sumner
It is possible, and one way to see an example would be to look in the raster package source. But, whether it will help depends on what the target software is. (GDAL 1.9.2 doesn't seem to understand the metadata written by raster for example.) On Sat, Aug 31, 2013 at 4:52 AM, Dominik Schneider wr

Re: [R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread GD
I had related situation with 85000 non-overlapping polygons, and a raster dataset with dimensions ~ 1x1. In that case I wanted the full distribution of pixel values inside each polygon, rather than just the mean. An efficient approach (much faster than extract) was: 1) Rasterize the polyg

Re: [R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread Michael Treglia
Tom - Thanks for the suggestion. You're right - for these coarse-scale data, the value at the centroid of the polygons would work, so I'll play with that and give it a whirl this weekend. I was thinking that if I'm using R, I would try to use the weighted average of the values of climate variabl

Re: [R-sig-Geo] Global mapping of multiple categories by colour

2013-08-30 Thread Andy South
> > Thanks Roger for your comprehensive answer, I've been offline for a couple of days. Sarah, I think you may be very close to your first objective. Try removing the quotes around data3, (because data3 is an object not a string) : malMap <- joinCountryData2Map(dF = data3, joinCode = "ISO3",

Re: [R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread Michael Treglia
Hi Tom, List members, Thanks for the reply. My polygons constitute a tiling of 100m or 200m square polygons, with no overlaps. I'll be trying to make predictions for the smaller scale, but some of my input variables like Climate are at coarser (800m) resolution, so I'm trying to combine these data

Re: [R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread Tom Philippi
Mike-- Do your 96000 polygons overlap (e.g., species ranges for 96k species), or do they constitute a tiling with tiny polygons relative to the raster cell size (e.g., a vegetation map v. coarse raster climate data)? Also, roughly how many vertices do your polygons have? I suspect that there isn'

Re: [R-sig-Geo] Global mapping of multiple categories by colour

2013-08-30 Thread Rhona Govender
Thank you for the help, everyone. Andy, this did fix the country matching problem! Thank you very much. I am now trying to divide the data into just 3 categories, but I will move this over to the google group. Cheers, Sarah On Fri, Aug 30, 2013 at 11:04 AM, Andy South wrote: >> > > > Thanks Ro

[R-sig-Geo] coordinate system in ncdf4

2013-08-30 Thread Dominik Schneider
Is it possible to specify the coordinate system when creating a netcdf file with the ncdf4 package? I have not been able to see anything in the documentation. Thanks [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-pro

[R-sig-Geo] Converting from spatial polygon to spatial lines

2013-08-30 Thread mattguzz...@gmail.com
I cannot seem to find a method for converting a spatial polygon class file to a spatial lines class. Most of the methods seem to be manually, but I am hoping there is a simpler method. Any help would be appreciated. Matt -- View this message in context: http://r-sig-geo.2731867.n2.nabble.com/C

Re: [R-sig-Geo] Converting from spatial polygon to spatial lines

2013-08-30 Thread mattguzz...@gmail.com
That was simple - Thanks! Now I just have to deal with the turning angles that are too large for the function I am using! Matt -- View this message in context: http://r-sig-geo.2731867.n2.nabble.com/Converting-from-spatial-polygon-to-spatial-lines-tp7584516p7584519.html Sent from the R-sig-geo

Re: [R-sig-Geo] Converting from spatial polygon to spatial lines

2013-08-30 Thread Andrew Vitale
I believe it's as simple as: as(yourObject, 'SpatialLines') On Fri, Aug 30, 2013 at 3:01 PM, mattguzz...@gmail.com < mattguzz...@gmail.com> wrote: > I cannot seem to find a method for converting a spatial polygon class file > to > a spatial lines class. Most of the methods seem to be manually,

[R-sig-Geo] (no subject)

2013-08-30 Thread Jochen Albrecht
[[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread Tom Philippi
Mike-- So that implies that you 96k tiny polygons aren't really polygons with area that matters, and certainly not area that you need to average the raster data over. What you have are streams, and you want to extract attributes from raster climate data along each stream. You could replace your 9

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Roger Bivand
On Fri, 30 Aug 2013, Paul Bidanset wrote: Thank you. I'd like to subset into a specific county. Should there be further partitioning from that level? No idea. Please re-create your scenario by subsetting georgia and the coordinates to suit. Roger On Fri, Aug 30, 2013 at 10:19 AM, Roger

Re: [R-sig-Geo] error - converting latlong to utm

2013-08-30 Thread Roger Bivand
Do not post HTML! Yes, you have reversed your eastings and northings, so -115N is out of bounds for obvious reasons. Roger On Fri, 30 Aug 2013, Ludmila Rattis wrote: Hi everyone, I tried to convert five different matrix of geographic coordinates using this code, but just two didn't work:

[R-sig-Geo] Extract function - too much data for R?

2013-08-30 Thread Michael Treglia
Hi All, I've been trying to use the extract function (in the raster packages) to get values of a raster entered as attributes of series of polygons, and have tested it successfully with a reduced dataset, but am concerned that my full dataset might be too big. My full datasets involve ~46000 and

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Paul Bidanset
Thank you. I'd like to subset into a specific county. Should there be further partitioning from that level? On Fri, Aug 30, 2013 at 10:19 AM, Roger Bivand wrote: > On Fri, 30 Aug 2013, Paul Bidanset wrote: > > Alrighty then! >> > > Thanks. Now make this your case by subsetting georgia in a way

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Roger Bivand
On Fri, 30 Aug 2013, Paul Bidanset wrote: Alrighty then! Thanks. Now make this your case by subsetting georgia in a way that matches your case (all counties west of x?, random set?), and we may be getting closer. In the geographical partition, the fit points are all a long way from the data

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Paul Bidanset
Alrighty then! Say I create this adaptive bandwidth model using the original dataset "georgia" coords = cbind(georgia$x, georgia$y) bwsel <- gwr.sel(PctBach ~ TotPop90 + PctRural + PctEld + PctFB + PctPov + PctBlack, data=georgia, adapt=TRUE, coords, gweight=gwr.Gauss, method = "aic" ) bw1 <- gw.

[R-sig-Geo] error - converting latlong to utm

2013-08-30 Thread Ludmila Rattis
Hi everyone, I tried to convert five different matrix of geographic coordinates using this code, but just two didn't work: *The code:* gila_centroid_latlong<-data.frame(Y=gila_centroid[,2],X=gila_centroid[,3]) coordinates(gila_centroid_latlong) <- ~ X + Y ##*And the error occurs here:*. proj4s

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Roger Bivand
Provide a reproducible code example of your problem using a built in data set. No reproducible example, no response, as I cannot guess (and likely nobody else can either) what your specific misunderstanding is. Code using for example the Georgia data set in the package. You seem to be assuming

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Paul Bidanset
Roger, I think all I would like to know is if it is possible to apply a calibrated GWR model to a hold-out sample, and if so, what the most accurate way to do so is. I understand the pitfalls of GWR but would like to learn as much as I can before progressing to the next spatial methodology I learn

[R-sig-Geo] Questions of bandwidth in pcf() function

2013-08-30 Thread yaobei
Dear all, Currently, I attempted to compare spatial aggregation of species across latitude. I plan to use pcf.ppp() function in ‘spatstat’ package. I also have a question about the parameter ‘bandwidth’ in pcf function.In pcf.ppp() function, the argument bw (bandwidth) is a default val

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Roger Bivand
Paul, Luis, I suspect that your speculations are completely wrong-headed. Please provide a reproducible example with a built-in data set, so that there is at least minimal clarity in what you are guessing. Note in addition that GWR as a technique should not be used for anything other than expl

Re: [R-sig-Geo] Holdout Sampling Adaptive Bandwidth SPGWR

2013-08-30 Thread Luis Guerra
> Thank you Luis. When calibrating the adaptive model, using adapt=t in the > bandwidth selection created the proportion you speak of, which then allowed > me to create a bandwidth matrix using gwr.adapt. However, this has not > worked for me with holdout samples. Have you had success in this regar