[R-sig-Geo] Same mask for two rasters, but obtaining different extents in R

[Vijay Ramesh]

I re-checked the original extent and here it is: This is data obtained from
WorldClim.

> bio5
class       : RasterLayer
dimensions  : 3600, 8640, 31104000  (nrow, ncol, ncell)
resolution  : 0.04166667, 0.04166667  (x, y)
extent      : -180, 180, -60, *90.00001 * (xmin, xmax, ymin, ymax) #This
varies at the 6th decimal place.
coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs
data source : C:\Users\rameshv\Downloads\Climate
Stability\Data_LGM_Present\Present\1_RawData\bio_5
names       : bio_5
values      : -86, 489  (min, max)
attributes  :
        ID COUNT
 from: -86     1
 to  : 489    38


> lg5
class       : RasterLayer
dimensions  : 3600, 8640, 31104000  (nrow, ncol, ncell)
resolution  : 0.04166667, 0.04166667  (x, y)
extent      : -180, 180, -60, 90  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs
data source : C:\Users\rameshv\Downloads\Climate
Stability\Data_LGM_Present\LGM\1_RawData\cclgmbi5.tif
names       : cclgmbi5
values      : -204, 519  (min, max)

What do you suggest?

Also, any suggestions on aligning them before I crop them? I wouldn't want
to projectRaster using one of the rasters, as that creates extra number of
rows (when I coerce the raster to a Spatial Pixels Data Frame).



On Wed, Mar 15, 2017 at 1:13 PM, Sarah Goslee <sarah.goslee at gmail.com>
wrote:

> The most likely explanation seems to me that the rasters were not
> aligned before cropping, so they are not aligned after cropping.
>
> Have you checked the original extent and resolution?
>
> Sarah
>
> On Tue, Mar 14, 2017 at 5:31 PM, Vijay Ramesh via R-sig-Geo
> <r-sig-geo at r-project.org> wrote:
> > I loaded a shapefile in R, and cropped and masked it with the same mask,
> > but I get different extents. Any suggestions?
> >
> > Code below:
> >
> >     library(raster)
> >     library(rgdal)
> >     library(GISTools)
> >     library(sp)
> >     library(maptools)
> >
> >     ##Loading the first mask
> >     Mask <- readOGR("C:\\Users\\rameshv\\Downloads\\Climate
> > Stability\\SPV_Mask\\mask.shp")
> >     proj4string(Mask) <- CRS("+init=epsg:4326")
> >
> >     #Loading the Rasters For Present and LGM and clipping them to the
> right
> > extent
> >     bio5 <- raster("C:\\Users\\rameshv\\Downloads\\Climate
> > Stability\\Data_LGM_Present\\Present\\1_RawData\\bio_5")
> >     proj4string(bio5) <- CRS("+init=epsg:4326")
> >     lg5 <- raster("C:\\Users\\rameshv\\Downloads\\Climate
> > Stability\\Data_LGM_Present\\LGM\\1_RawData\\cclgmbi5.tif")
> >     proj4string(lg5) <- CRS("+init=epsg:4326")
> >
> >     ##Cropping by using the Crop and Mask functions
> >     cr<- crop(bio5, extent(Mask))
> >     bio5 <- mask(cr, Mask)
> >
> >     cr2<- crop(lg5, extent(Mask))
> >     lg5<- mask(cr2, Mask)
> >
> >     > bio5
> >      class       : RasterLayer
> >      dimensions  : 339, 246, 83394  (nrow, ncol, ncell)
> >      resolution  : 0.04166667, 0.04166667  (x, y)
> >      extent      : 72.45835, 82.70835, 8.083337, 22.20834  (xmin, xmax,
> > ymin, ymax)
> >      coord. ref. : +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs
> > +ellps=WGS84 +towgs84=0,0,0
> >      data source : in memory
> >      names       : bio_5
> >      values      : 207, 432  (min, max)
> >      attributes  :
> >         ID COUNT
> >      from: -86     1
> >      to  : 489    38
> >
> >      > lg5
> >      class       : RasterLayer
> >      dimensions  : 339, 246, 83394  (nrow, ncol, ncell)
> >      resolution  : 0.04166667, 0.04166667  (x, y)
> >      extent      : 72.45833, 82.70833, 8.083333, 22.20833  (xmin, xmax,
> > ymin, ymax)
> >      coord. ref. : +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs
> > +ellps=WGS84 +towgs84=0,0,0
> >      data source : in memory
> >      names       : cclgmbi5
> >      values      : 187, 392  (min, max)
> >
> >
>
> --
> Sarah Goslee
> http://www.functionaldiversity.org
>



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