ursa (version 3.10.4)

as.ursa: Create raster image from R objects or GDAL raster files.

Description

as.ursa converts R base objects matrix, array, numeric, data.frame list, sp objects SpatialGridDataFrame, SpatialPixelsDataFrame and SpatialPointsDataFrame, raster objects raster, stack and brick, and GDAL raster files (using functions from rgdal package) to ursaRaster object.

Usage

as.ursa(obj, ...)
as_ursa(obj, ...)

Value

Object of class ursaRaster

Arguments

obj

R object for coercion

...

Depending on class of obj, arguments are passed to repsective functions.

Author

Nikita Platonov

Details

as_ursa is a synonym to as.ursa.

This is a high-level function to create ursaRaster objects. The follwed classes of R objects are implemented:

‘Data Class’	‘Appropriate method’	array
ursa_new	matrix	ursa_new
numeric	ursa_new	data.frame
allocate	SpatialPointsDataFrame (sp)	allocate
SpatialPixelsDataFrame (sp)	allocate	SpatialGridDataFrame (sp)
ursa_new	list of ursaRaster objects	unlist
list returned by sf::gdal_read	ursa_new	list (general)
Items $x and $y are required, If lengths of $x and $y are equal to dim of data, then allocate, else: 1) raster grid is defined from $x and $y, 2) ursa_new is called.	ggmap (ggmap)	ursa_new.
raster (raster)	ursa_new.	brick (raster)
ursa_new.	stack (raster)	ursa_new.
bitmap (magick)	ursa_new.	character (GDAL supported file name)

Generally, allocate is used for objects with non-regular grid, and ursa_new is used for regular grids. The raster grid is defined from object properties or from sessional grid.

Color tables are supported for GDAL file names and raster objects (raster, brick, stack).

For ENVI *.hdr Labelled Raster Files there are alternatives:

1. Read object with GDAL (read_gdal);

2. Read object without GDAL (read_envi).

Examples

session_grid(NULL)
a1 <- as.ursa(volcano)
print(a1)
display(a1)

session_grid(NULL)
b <- ursa_dummy(mul=1/16,bandname=format(Sys.Date()+seq(3)-1,"%A"))
print(b)

c1 <- b[[1]] ## equal to 'c1 <- as.matrix(b[1],coords=TRUE)'
str(c1)
b1a <- as.ursa(c1)
print(c(original=b[1],imported=b1a))
print(c(projection.b1a=ursa_proj(b1a)))
session_grid(NULL)
b1b <- as.ursa(c1$z)
print(b1b)
print(c(projection.b1b=ursa_proj(b1b)))

c2 <- as.data.frame(b)
str(c2)
session_grid(NULL)
b2a <- as.ursa(c2)
print(b2a)

session_grid(NULL)
attr(c2,"crs") <- NULL
b2b <- as.ursa(c2)
print(b2b)
print(ursa_grid(b2b))

c3 <- unclass(as.matrix(b,coords=TRUE))
str(c3)
session_grid(b)
b3a <- as.ursa(c3)
print(b3a)
print(ursa_grid(b3a))
session_grid(NULL)
b3b <- as.ursa(c3)
print(b3b)
print(ursa_grid(b3b))

c4 <- as.array(b)
str(c4)
session_grid(b)
b4a <- as.ursa(c4)
print(b4a)
print(ursa_grid(b4a))
session_grid(NULL)
b4b <- as.ursa(c4)
print(b4b)
print(ursa_grid(b4b))

n <- 20
c5 <- data.frame(y=runif(n,min=1000000,max=5000000)
                ,x=runif(n,min=-3000000,max=1000000)
                ,value=runif(n,min=0,max=10))
print(head(c5))
session_grid(b)
b5a <- as.ursa(c5)
print(b5a)
 ## to avoid over-timing during tests -- begin
   display(b5a)
 ## to avoid over-timing during tests -- end
session_grid(NULL)
b5b <- as.ursa(c5)
print(b5b)
 ## to avoid over-timing during tests -- begin
   display(b5b)
 ## to avoid over-timing during tests -- end

# b6 <- as.ursa(system.file("pictures/erdas_spnad83.tif",package="rgdal"))
b6 <- as.ursa(system.file("tif/geomatrix.tif",package="sf"))
print(b6)
display(b6,pal=c("black","white"),coast=FALSE,col="orange")

 ## package 'raster' is required -- begin
if (requireNamespace("raster")) {
   r <- raster::brick(system.file("external/rlogo.gri",package="raster"))
   print(r)
   b7 <- as.ursa(r)
   ursa_proj(b7) <- ""
   print(b7)
   display_rgb(b7)
}
 ## package 'raster' is required -- end