add_rugged_terrain: Add rugged terrain information to a data frame

In svmiller/peacesciencer: Tools and Data for Quantitative Peace Science Research

Add rugged terrain information to a data frame

Description

add_rugged_terrain() allows you to add information, however crude, about the "ruggedness" of a state's terrain to your (dyad-year, leader-year, leader-dyad-year, state-year) data.

Usage

add_rugged_terrain(data)

Arguments

data	a data frame with appropriate peacesciencer attributes

Details

Please see the information for the underlying data rugged, and the associated R script in the data-raw directory, to see how these data are generated. Importantly, these data are time-agnostic and move slowly. We're talking about geography here. Both data sets benchmark around 1999-2000 and it's a leap of faith to use these data for comparisons across the entirety of the Correlates of War or Gleditsch-Ward system membership. Every use of data of these types have been either cross-sectional snapshots or for making state-to-state comparisons after World War II (think of your prominent civil war studies here). Be mindful about what you expect to get from these data.

The data have both Gleditsch-Ward codes and Correlates of War codes. The merge it makes depends on what you declare as the "master" system at the top of the pipe (e.g.. in create_dyadyears() or create_stateyears()). If, for example, you run create_stateyears(system="cow") and follow it with add_gwcode_to_cow(), the merge will be on the Correlates of War codes and not the Gleditsch-Ward codes. You can see the script mechanics to see how this is achieved.

Value

add_rugged_terrain() takes a (dyad-year, leader-year, leader-dyad-year, state-year) data frame, whether the primary state identifiers are from the Correlates of War system or the Gleditsch-Ward system, and returns information about the "ruggedness" of the state's terrain. The two indicators returned are the "terrain ruggedness index" calculated by Nunn and Puga (2012) and a logarithmic transformation of how mountainous the state is (as calculated by Gibler and Miller, 2014). The dyad-year (leader-dyad-year) data get four additional columns (i.e. both indicators for both states in the dyad) whereas the state-year data get just the two additional columns.

Author(s)

Steven V. Miller

References

Fearon, James D., and David Laitin, "Ethnicity, Insurgency, and Civil War" American Political Science Review 97: 75–90.

Gibler, Douglas M. and Steven V. Miller. 2014. "External Territorial Threat, State Capacity, and Civil War." Journal of Peace Research 51(5): 634-646.

Nunn, Nathan and Diego Puga. 2012. "Ruggedness: The Blessing of Bad Geography in Africa." Review of Economics and Statistics. 94(1): 20-36.

Riley, Shawn J., Stephen D. DeGloria, and Robert Elliot. 1999. "A Terrain Ruggedness Index That Quantifies Topographic Heterogeneity,” Intermountain Journal of Sciences 5: 23–27.

Examples

# just call `library(tidyverse)` at the top of the your script
library(magrittr)

cow_ddy %>% add_rugged_terrain()

create_stateyears() %>% add_rugged_terrain()

create_stateyears(system = "gw") %>% add_rugged_terrain()

svmiller/peacesciencer documentation built on July 16, 2025, 7:01 p.m.