sprawlext class

An S4 class to represent the extent of a spatial object, associated with its proj4string.
Slots

extent: numeric (4) extent of the object (xmin, ymin, xmax, ymax)
proj4string: character proj4string of the object
Examples


showClass("sprawlext")
#> Class "sprawlext" [package "sprawl"]
#> 
#> Slots:
#>                               
#> Name:       extent proj4string
#> Class:     numeric   character
library(raster)

in_rast <- system.file("extdata/MODIS_test", "EVIts_test.tif",
  package = "sprawl.data")
ex_sprawlext <- get_extent(in_rast)

# Convert sprawlext to Extent
ex_extent <- as(ex_sprawlext, "Extent")
ex_extent
#> class       : Extent 
#> xmin        : 12897004 
#> xmax        : 12973683 
#> ymin        : 1685995 
#> ymax        : 1789545 

# Convert to bbox
ex_bbox <- as(ex_sprawlext, "matrix")
ex_bbox
#>        min      max
#> x 12897004 12973683
#> y  1685995  1789545

# Convert to Spatial* objects
as(ex_sprawlext, "SpatialPolygons")
#> class       : SpatialPolygons 
#> features    : 1 
#> extent      : 12897004, 12973683, 1685995, 1789545  (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs 
as(ex_sprawlext, "SpatialPoints")
#> class       : SpatialPoints 
#> features    : 4 
#> extent      : 12897004, 12973683, 1685995, 1789545  (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs 
as(ex_sprawlext, "SpatialLines")
#> class       : SpatialLines 
#> features    : 1 
#> extent      : 12897004, 12973683, 1685995, 1789545  (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs 

# Convert to sf objects
as(ex_sprawlext, "sfc_POLYGON")
#> Geometry set for 1 feature 
#> geometry type:  POLYGON
#> dimension:      XY
#> bbox:           xmin: 12897000 ymin: 1685995 xmax: 12973680 ymax: 1789545
#> epsg (SRID):    NA
#> proj4string:    +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs
#> POLYGON ((12897004 1685995, 12897004 1789545, 1...
as(ex_sprawlext, "sfc_POINT")
#> Geometry set for 4 features 
#> geometry type:  POINT
#> dimension:      XY
#> bbox:           xmin: 12897000 ymin: 1685995 xmax: 12973680 ymax: 1789545
#> epsg (SRID):    NA
#> proj4string:    +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs
#> POINT (12897004 1685995)
#> POINT (12897004 1789545)
#> POINT (12973683 1789545)
#> POINT (12973683 1685995)

# Extract proj4string CRS
ex_crs <- as(ex_sprawlext, "CRS")
ex_crs
#> CRS arguments:
#>  +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181
#> +units=m +no_defs 

# Create sprawlext from extent and CRS
get_extent(ex_extent, ex_crs)
#> An object of class "sprawlext"
#> Slot "extent":
#>     xmin     ymin     xmax     ymax 
#> 12897004  1685995 12973683  1789545 
#> 
#> Slot "proj4string":
#> [1] "+proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs"
#> 

# Create sprawlext from bbox and CRS
get_extent(ex_bbox, ex_crs)
#> An object of class "sprawlext"
#> Slot "extent":
#>     xmin     ymin     xmax     ymax 
#> 12897004  1685995 12973683  1789545 
#> 
#> Slot "proj4string":
#> [1] "+proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs"
#>
Slots

Examples

Contents
