Wednesday, December 11, 2024

The Interactive Murder Map

map showing the locations of mursers in Norway

Norwegian newspaper VG has been mapping murders in Norway since the turn of the millennium. The cumulative data in Murder in Norway allows the paper to provide some fascinating insights into Norwegian homicides. For example, this year, 61% of murder victims have been killed by a family member or a partner/ex-partner. Last year, 45% of murder victims were killed by their partner or ex-partner. Unsurprisingly, in most of those cases, the victim was a woman killed by her male partner or ex-partner. So far this century, 90% of murders in Norway have been carried out by men.

Drap i Norge has used VG's homicide data to create an interactive map of all Norwegian murders since 2000. This map plots where each murder occurred and allows users to filter the results by murder weapon and the murderer's country of birth. Pen portraits of each murder victim are also displayed in the map sidebar.

I rarely review crime maps on Maps Mania because I often find them uninformative. One major issue with most crime maps is that they only plot crimes reported to the police, which can be misleading. For example, I have had three or four bikes stolen over the last 20 years and have never reported any of these thefts to the police. 

I suspect that unreported crime is less of an issue with homicides, making murder maps somewhat more reliable. However, despite being less affected by data collection issues, a 'murder map' still has many of the shortcomings commonly associated with crime maps. For instance, VG's Murder in Norway map (shown below) misleadingly appears to suggest that people are far more likely to be murdered in the south of the country than in the north.

map showing the locations of mursers in Norway
The reality, of course, is quite different. Both the Drap i Norge interactive map and VG's Murder in Norway map are simple plots of all the murders that have occurred in Norway this century. Neither map normalizes the data by population.

In data visualization, normalizing by population means adjusting data values to account for differences in population size, enabling fairer comparisons between different regions. The density of red dots on both Drap i Norge and Murder in Norway maps is merely a reflection of population density, offering little insight into murder rates across the country.

Instead of displaying raw totals, which can be misleading, these maps could provide the option to normalize the data 'per capita' for each county. This would give viewers a much clearer picture of murder rates across the different regions of Norway. To be really informative the maps could even provide other demographic and socioeconomic data layers - allowing the user to explore what may be some of the underlying contributing factors to localized homicide rates.

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