Re: [R-sig-Geo] using readGDAL() for ESRI raster file

On Thu, 1 Jun 2006 [EMAIL PROTECTED] wrote: > Hello list > > thanks to the helpful advice given by list members I have been able to read > and re-project vector based shape files and attributes data using readOGR() > under rgdal for further analysis (kriging, k-means clustering) and > plotting. >

[R-sig-Geo] using readGDAL() for ESRI raster file

Hello list thanks to the helpful advice given by list members I have been able to read and re-project vector based shape files and attributes data using readOGR() under rgdal for further analysis (kriging, k-means clustering) and plotting. Using the sp.layout under spplot allowed me to precisely

[R-sig-Geo] Availability of R Script for WSAF(weighted spatial adaptive filter)

Hi. Does any one know whether R Script written for WSAF(weighted spatial adaptive filter)(Gorr, W.L. and Olligschlaeger, A.M. (1994). "Weighted Spatial Adaptive Filtering: Monte Carlo Studies and Application to Illicit Drug Market Modeling." Geographical Analysis, 26: 67-87. ), which enhances ad

Re: [R-sig-Geo] Computing polygon area with decimal degree coordinates

Yes, agreed... I realized that after having formulated the question and posted it Tim Keitt a écrit : > Do you mean the flat-plane area or the area projected onto the surface > of the ellipsoid? In either case, the computation is likely > non-trivial. It makes much more sense to project to

Re: [R-sig-Geo] Computing polygon area with decimal degree coordinates

Do you mean the flat-plane area or the area projected onto the surface of the ellipsoid? In either case, the computation is likely non-trivial. It makes much more sense to project to UTM and do the calculation there. THK On 5/31/06, Patrick Giraudoux <[EMAIL PROTECTED]> wrote: > > Dear Listers, >

Re: [R-sig-Geo] raster to polygons

didier leibovici kirjoitti: > Hi, > I can't find a function allowing to transform a raster grid to a polygon > 'shapefile' (sp class or other) I just posted on gdal-dev this example: http://map.hut.fi/PerlForGeoinformatics/scripts/r2v.pl It converts a grid to a layer of polygons, currently it is

Re: [R-sig-Geo] raster to polygons

On Wed, 31 May 2006, didier leibovici wrote: > Hi, > I can't find a function allowing to transform a raster grid to a polygon > 'shapefile' (sp class or other) Could you look in the sp package at: ?as.SpatialPolygons.GridTopology and see if it does what you need (for coarse grids)? It only mak

Re: [R-sig-Geo] Computing polygon area with decimal degree coordinates

On Wed, 31 May 2006, Patrick Giraudoux wrote: > Well, thinking about it, I realize this question was a bit weird/silly > in the real world... Decimal degree coordinates does not tell us > anything about the ellipsoid/datum they refer to and this must be done > within a CRS framework. If we want

[R-sig-Geo] raster to polygons

Hi, I can't find a function allowing to transform a raster grid to a polygon 'shapefile' (sp class or other) thanks -- Didier Leibovici Skype: didier_us166 [EMAIL PROTECTED] http://didier.leibovici.free.fr IRD US 166 Désertification http://www.us166.ird.fr/ Maison de la Télédét

Re: [R-sig-Geo] Computing polygon area with decimal degree coordinates

Well, thinking about it, I realize this question was a bit weird/silly in the real world... Decimal degree coordinates does not tell us anything about the ellipsoid/datum they refer to and this must be done within a CRS framework. If we want a reasonable precision on small areas, sound mathemat

Re: [R-sig-Geo] Computing polygon area with decimal degree coordinates

On Wed, 31 May 2006, Patrick Giraudoux wrote: > Dear Listers, > > The function areapl() of the package splancs computes polygon areas in > the coordinate units. This means in square meters when using UTM or > Lambert projections but in "square degrees" when using longlat degrees. > > Does any