geopackage.Rmd

geopackage.Rmd

---
title: "geopackage"
author: "Matt Jones"
date: "7/23/2021"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r load_libraries}
library(sf)
```

This is a simple overview/test of using GeoPackage in R, building off of the tutorial [Reading and writing spatial data in R](https://mgimond.github.io/Spatial/app1-1.html#app1_2).

## Determine the layers in a GeoPackage

```{r layers}
temp <- tempdir()
gpkg_file <- paste0(temp, "/rail_inters.gpkg")
download.file("http://github.com/mgimond/Spatial/raw/master/Data/rail_inters.gpkg", 
              destfile = gpkg_file, mode='wb')
st_layers(gpkg_file)
```


## Read in the layers

```{r}
inter.sf <- st_read(gpkg_file, layer="Interstate")
rail.sf  <- st_read(gpkg_file, layer="Rail")
```


## Write a geopackage 

```{r gpkg_export}
st_write(inter.sf, "rail_inters_export.gpkg", layer="interstates", delete_layer = TRUE)
st_write(rail.sf, "rail_inters_export.gpkg", layer="railways", delete_layer = TRUE)
st_layers("rail_inters_export.gpkg")
```

## Add a layer from a shapefile

```{r from_shp}
nc.sf = st_read(system.file("shape/nc.shp", package="sf"))
st_write(nc.sf, "rail_inters_export.gpkg", layer="nc", delete_layer = TRUE)
st_layers("rail_inters_export.gpkg")
```
## Add a shapefile from the KNB
```{r}
# Shapefile from:
# Christopher J Lortie, Jenna Braun, and Michael Belanger. 2019. York University Tree Inventory. Knowledge Network for Biocomplexity. doi:10.5063/F13F4MZC 
trees_url <- "https://knb.ecoinformatics.org/knb/d1/mn/v2/object/urn%3Auuid%3Adb829485-7d77-4b06-b35f-58f6e8f02e9f"
download.file(trees_url, destfile = paste0(temp, "/YorkUTreeMap.zip"), mode='wb')
unzip(paste0(temp,"/YorkUTreeMap.zip"), exdir=temp)
trees.sf <- st_read(paste0(temp, "/YorkUTreeMap.shp"))
st_write(trees.sf, "rail_inters_export.gpkg", layer="trees", delete_layer = TRUE)
st_layers("rail_inters_export.gpkg")
```