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Reads the CShapes 2.0 raw data

Source: R/data_cshapes.R
read_cshapes.Rd

Downloads and processes CShapes 2.0 historical country boundaries data. The function formats date columns and adds utility columns for temporal analysis compatible with PRIO-GRID.

Usage

read_cshapes()

Value

A sf object containing historical country boundaries with:

  • Geometry: Polygon/multipolygon country boundaries

  • gwsdate, gwedate: Properly formatted Date objects for country periods

  • date_interval: Utility column for temporal analysis

  • Coordinate reference system: WGS84 (EPSG:4326)

Details

CShapes 2.0 provides historical country boundary data from 1886 onwards at high spatial resolution. This function:

  • Downloads the CShapes 2.0 dataset if not already cached

  • Converts gwsdate and gwedate columns to proper Date objects

  • Adds a date_interval utility column for temporal operations

  • Returns data in sf format for spatial operations

References

Schvitz G, Girardin L, Rüegger S, Weidmann NB, Cederman L, Gleditsch KS (2022). “Mapping the International System, 1886-2019: The CShapes 2.0 Dataset.” Journal of Conflict Resolution, 66(1), 144–161. ISSN 0022-0027, doi:10.1177/00220027211013563 , 2024-11-22.

See also

pg_dates for PRIO-GRID temporal coverage, st_sf for sf object details

Examples

if (FALSE) { # \dontrun{
# Read CShapes 2.0 data
cshapes_data <- read_cshapes()

# Examine the structure
print(cshapes_data)

# Check date formatting
head(cshapes_data$gwsdate)
head(cshapes_data$gwedate)

# View available columns
names(cshapes_data)

# Filter to specific time period
modern_boundaries <- cshapes_data[cshapes_data$gwsdate >= as.Date("2000-01-01"), ]

# Plot boundaries for a specific period
plot(sf::st_geometry(modern_boundaries), main = "Country Boundaries (2000+)")
} # }