geoarrowWidget

The aim of geoarrowWidget is to facilitate fast transfer of geospatial data between R memory and the browser using geoarrow memory layout. It provides functionality to attach geoarrow data to existing htmlwidgets along with the relevant JavaScript libraries to handle this data in the browser context. It does not do anything useful beyond the data transfer. It is up to the user/devloper to make further use of this data, e.g. render it somehow, using JavaScript.

Installation

Not on CRAN yet, so install from github:

remotes::install_github("r-spatial/geoarrowWidget")

Usage example

For testing purposes, geoarrowWidget provides a minimal htmlwidget called geoarrowDummyWidget. Here’s an example of how to use it:

library(geoarrowWidget)
library(wk)
library(nanoarrow)
library(geoarrow)

### generate some random sf points data ========================================
n = 1e5
dat = data.frame(
  id = 1:n
  , geometry = xy(
    x = runif(n, -160, 160)
    , y = runif(n, -40, 40)
    , crs = 4326
  )
)

### setup and write to tempfile as geoarrow ====================================
fl = tempfile()
dir.create(fl)
path = file.path(
  fl
  , "test.arrow"
)

interleaved = FALSE

data_stream = nanoarrow::as_nanoarrow_array_stream(
  dat
  , geometry_schema = geoarrow::infer_geoarrow_schema(
    dat
    , coord_type = ifelse(interleaved, "INTERLEAVED", "SEPARATE")
  )
)

nanoarrow::write_nanoarrow(data_stream, path)

### create widget and check browser console ====================================
wgt = geoarrowDummyWidget(file = path)

options(viewer = NULL)

wgt

This will create a web page with the data attached as a geoarrow object. In the browser console (press F12) this will look something like this (depending on the browser obviously, Librewolf in this case)

The page source (press <CTRL + u>) will look something like this, where in line 11 you see the attached test.arrow file and above the necessary scripts (arrow and geoarrow JS bindings) to process the data further in JavaScript.

The general usage pattern is highlighted in these lines of geoarrowDummyWidget

Acknowledgment

This project has been realized with financial support from the