Mapping property crime rates in Poland

For this exercise, you must create a script containing the code needed to make an interactive map of property offences in counties (powiats) in Poland in 2023.

Before you start

Complete Chapters 1–5 and 9 of Learn Crime Mapping with R.

In this exercise you will practise downloading and reading data, data wrangling, selecting records for one year, combining datasets, calculating rates and creating an interactive choropleth map using leaflet.

What your map must show

Your map must show the incidence rate of property offences per 100,000 residents in 2023 in each powiat (county) in Poland. You will need three datasets to produce this map:

Property offence counts for each powiat in Excel format: https://mpjashby.github.io/crimemappingdata/poland_property_crime_counts.xlsx

Population data for each powiat in tab-separated (TSV) format: https://mpjashby.github.io/crimemappingdata/poland_population.tsv

Powiat boundaries in geopackage format: https://mpjashby.github.io/crimemappingdata/poland_powiat_boundaries.gpkg

See the documentation for the property offence counts, population and powiat boundaries for the columns and sources. The offence and population counts cover 2022–24: select only records where rok (year) is 2023. The offence counts relate to completed preparatory proceedings; the population is measured on 31 December 2023. The boundaries come from the 2025 archive. Acknowledge Statistics Poland (CC BY 4.0) and GUGiK/PRG as described in the documentation.

Your map must include:

  1. a layer showing the incidence rate of property offences in each powiat,
  2. a suitable base map,
  3. the contextual information (title etc.) needed to help readers understand the map properly.

Your map should use the leaflet functions introduced in Chapter 9 of the textbook, including a legend, labels showing each powiat’s name and rate, and an inset map.

Every step of your code should be accompanied by an explanatory comment (on one or more lines starting with a # symbol and a space). Your code should only produce a map (and possibly some R messages or warnings), not output anything else (e.g. a copy of the data).

Leave the leaflet stack unassigned so that running it in the R Console displays the map directly. Do not store the map in an object or save it as an HTML file.

Checklist for this exercise

Make sure you have checked that your map and code meet all of the following requirements.

The map

  • The map shows the incidence rate of property offences in each powiat in 2023.
  • The incidence rates are shown using an appropriate sequential (not diverging or qualitative) colour scheme.
  • The most visually prominent colour indicates the highest rates of property crime.
  • The map shows the boundary of each powiat.
  • The map includes a suitable base map.
  • The base map does not distract from the data layer or make it harder to see the data layer.
  • It is possible to see the base map through the layer that shows the property crime rate.
  • The map identifies the place, year and rate units.
  • The map acknowledges Statistics Poland (CC BY 4.0) and GUGiK/PRG as the data sources.
  • You have made design choices that make it as easy as possible to show where the property crime rate is highest.
  • You have made design choices that make sure the boundaries do not obscure the places with the highest rates of crime.

The code

  • There is no temporary code – e.g. head() or install.packages() – in your script file.
  • The code loads all the necessary packages at the start of the script.
  • The code downloads the data file from the URL to a local file and then loads it.
  • The code converts all the column names in the data to snake_case and only uses snake-case object names.
  • The code reads the boundaries as an SF object.
  • The code selects 2023 only from both statistical datasets, joins the datasets correctly and calculates offences per 100,000 residents.
  • Every step of your code is accompanied by an explanatory comment.
  • The leaflet stack displays the map directly without storing it in an object or saving it as an HTML file.

Check your answer

After attempting the task, you can read this specimen answer and explanation to get an idea of what a potential solution looks like.