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README.Rmd
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README.Rmd
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---
output: github_document
---
<!-- README.md is generated from README.Rmd. Please edit that file -->
```{r, include = FALSE}
knitr::opts_chunk$set(
collapse = TRUE,
comment = "#>",
fig.path = "man/figures/README-",
out.width = "100%"
)
```
# geotargets
<!-- badges: start -->
[](https://www.repostatus.org/#wip)
[](https://wlandau.github.io/targetopia/)
[](https://github.com/njtierney/geotargets/actions/workflows/R-CMD-check.yaml)
[](https://app.codecov.io/gh/njtierney/geotargets?branch=master)
<!-- badges: end -->
`geotargets` extends targets to work with geospatial data formats, such as rasters and vectors (e.g., shapefiles).
A relatively common gotcha moment when using popular libraries like `terra` with targets is running into erros with read and write. Due to the limitations that come with the underlying C++ implementation in the `terra` library, there are specific ways to write and read these objects. See `?terra` for details. `geotargets` helps handle these write and read steps, so you don't have to worry about them and can use targets as you are used to.
In essence, if you've ever come across the error:
```
Error in .External(list(name = "CppMethod__invoke_notvoid", address = <pointer: 0x0>, :
NULL value passed as symbol address
```
or
```
Error: external pointer is not valid
```
When trying to read in a geospatial raster or vector in targets, then this is for you :)
## Installation
You can install the development version of geotargets like so:
``` r
install.packages("geotargets", repos = c("https://njtierney.r-universe.dev", "https://cran.r-project.org"))
```
## A note on development
`geotargets` is still undergoing development, and we would love for people to use the package to kick the tyres. We are using it in our own work, but want users to know that the API could change in subtle or breaking ways.
# Examples
Below we show two examples of target factories:
- `tar_terra_rast()`
- `tar_terra_vect()`
You would use these in place of `tar_target()` in your targets pipeline, when you are doing work with terra raster or terra vector data.
It is a bit tricky to implement targets workflows in a README, but if you would like to see and download working examples for yourself, see the repo, [demo-geotargets](https://github.com/njtierney/demo-geotargets).
## `tar_terra_rast()`: targets with terra rasters
```{r}
#| label: tar-terra-rast
#| eval: false
library(targets)
tar_dir({ # tar_dir() runs code from a temporary directory.
tar_script({
library(targets)
library(geotargets)
list(
tar_terra_rast(
terra_rast_example,
system.file("ex/elev.tif", package = "terra") |> terra::rast()
)
)
})
tar_make()
x <- tar_read(terra_rast_example)
x
})
```
## `tar_terra_vect()`: targets with terra vectors
```{r}
#| label: tar-terra-vect
#| eval: false
tar_dir({ # tar_dir() runs code from a temporary directory.
tar_script({
library(geotargets)
lux_area <- function(projection = "EPSG:4326") {
terra::project(
terra::vect(system.file("ex", "lux.shp",
package = "terra"
)),
projection
)
}
list(
tar_terra_vect(
terra_vect_example,
lux_area()
)
)
})
tar_make()
x <- tar_read(terra_rast_example)
x
})
```
## Code of Conduct
Please note that the geotargets project is released with a [Contributor Code of Conduct](https://contributor-covenant.org/version/2/1/CODE_OF_CONDUCT.html). By contributing to this project, you agree to abide by its terms.