The goal of wk is to provide lightweight R, C, and C++ infrastructure for a distributed ecosystem of packages that operate on collections of coordinates. First, wk provides vector classes for points, circles, rectangles, well-known text (WKT), and well-known binary (WKB). Second, wk provides a C API and set of S3 generics for event-based iteration over vectors of geometries.
You can install the released version of wk from CRAN with:
install.packages("wk")You can install the development version from GitHub with:
# install.packages("remotes")
remotes::install_github("paleolimbot/wk")If you can load the package, you’re good to go!
library(wk)Use wkt() to mark a character vector as containing
well-known text, or wkb() to mark a vector as well-known
binary. Use xy(), xyz(), xym(),
and xyzm() to create vectors of points, and
rct() to create vectors of rectangles. These classes have
full vctrs support and
plot()/format() methods to make them as
frictionless as possible working in R and RStudio.
wkt("POINT (30 10)")
#> <wk_wkt[1]>
#> [1] POINT (30 10)
as_wkb(wkt("POINT (30 10)"))
#> <wk_wkb[1]>
#> [1] <POINT (30 10)>
xy(1, 2)
#> <wk_xy[1]>
#> [1] (1 2)
rct(1, 2, 3, 4)
#> <wk_rct[1]>
#> [1] [1 2 3 4]
crc(0, 0, 1)
#> <wk_crc[1]>
#> [1] [0 0, r = 1]The wk package is made up of readers, handlers, and filters. Readers
parse the various formats supported by the wk package, handlers
calculate values based on information from the readers (e.g.,
translating a vector of geometries into another format), and filters
transform information from the readers (e.g., transforming coordinates)
on the fly. The wk_handle() and wk_translate()
generics power operations for many geometry vector formats without
having to explicitly support each one.
The distributed nature of the wk framework is powered by a ~100-line header describing the types of information that parsers typically encounter when reading geometries and the order in which that information is typically organized. Detailed information is available in the C and C++ API article.
wk_debug(
as_wkt("LINESTRING (1 1, 2 2, 3 3)"),
wkt_format_handler(max_coords = 2)
)
#> initialize (dirty = 0 -> 1)
#> vector_start: <Unknown type / 0>[1] <0x16d75aac0> => WK_CONTINUE
#> feature_start (1): <0x16d75aac0> => WK_CONTINUE
#> geometry_start (<none>): LINESTRING[UNKNOWN] <0x16d75a950> => WK_CONTINUE
#> coord (1): <0x16d75a950> (1.000000 1.000000) => WK_CONTINUE
#> coord (2): <0x16d75a950> (2.000000 2.000000) => WK_ABORT_FEATURE
#> vector_end: <0x16d75aac0>
#> deinitialize
#> [1] "LINESTRING (1 1, 2 2..."The wk package implements a reader and writer for sfc objects so you
can use them wherever you’d use an xy(),
rct(), crc(), wkb(), or
wkt():
wk_debug(
sf::st_sfc(sf::st_linestring(rbind(c(1, 1), c(2, 2), c(3, 3)))),
wkt_format_handler(max_coords = 2)
)
#> initialize (dirty = 0 -> 1)
#> vector_start: LINESTRING B[1] <0x16d75dac8> => WK_CONTINUE
#> feature_start (1): <0x16d75dac8> => WK_CONTINUE
#> geometry_start (<none>): LINESTRING[3] <0x16d75da10> => WK_CONTINUE
#> coord (1): <0x16d75da10> (1.000000 1.000000) => WK_CONTINUE
#> coord (2): <0x16d75da10> (2.000000 2.000000) => WK_ABORT_FEATURE
#> vector_end: <0x16d75dac8>
#> deinitialize
#> [1] "LINESTRING (1 1, 2 2..."The wk package has zero dependencies and compiles in ~10 seconds.