runzipterra

R read zip-file, gpkg-file with terra vect()

I have two questions on applying vect of the package terra with files from an opendata-source.

  1. I would like to read the shp-file with vect from the directory "Amphibien_LV95" within the zip-file "data" without downloading and unzipping the file locally.
link <- https://data.geo.admin.ch/ch.bafu.bundesinventare-amphibien/data.zip

Unfortunately my attempts with unz and unzip in combination with vect() were not successful.

  1. I would like to read a gpkg-File from an http-address (in special the layer=ElectricityProductionPlant)
link <- "https://data.geo.admin.ch/ch.bfe.elektrizitaetsproduktionsanlagen/gpkg/2056/ch.bfe.elektrizitaetsproduktionsanlagen.gpkg"

data <- vect(link)

With vect() I get the error:

Error: [vect] cannot read this geometry type: Unknown (any)

If I read the link with st_read and then transform it with vect it works. Why?

a <- st_read(link)
data <- vect(a)
Solution

  • VSI handlers can also be chained, so we could use zip + curl for the 1st:

    library(terra)
#> terra 1.7.83
zip_link <- "https://data.geo.admin.ch/ch.bafu.bundesinventare-amphibien/data.zip"
(vsi <- paste("/vsizip", "/vsicurl", zip_link, "Amphibien_LV95", sep = "/" ))
#> [1] "/vsizip//vsicurl/https://data.geo.admin.ch/ch.bafu.bundesinventare-amphibien/data.zip/Amphibien_LV95"
vector_layers(vsi)
#> [1] "am_A3"              "amphibLaichgebiet"  "amphibWanderobjekt"
vect(vsi, layer = "amphibLaichgebiet")[,1:4]
#>  class       : SpatVector 
#>  geometry    : polygons 
#>  dimensions  : 1448, 4  (geometries, attributes)
#>  extent      : 2486326, 2830988, 1075278, 1291233  (xmin, xmax, ymin, ymax)
#>  source      : Amphibien_LV95 (amphibLaichgebiet)
#>  coord. ref. : CH1903+ / LV95 (EPSG:2056) 
#>  names       : ObjNummer           Name                RefObjBlat DesignatTy
#>  type        :     <chr>          <chr>                     <chr>      <chr>
#>  values      :       AG3 Zurlindeninsel https://data.geo.admin.c~        NDA
#>                     AG19       Halbmond https://data.geo.admin.c~        NDA
#>                     AG19       Halbmond https://data.geo.admin.c~        NDA