Swiss Municipal Data Merger Tool: Manual

Introduction

In Switzerland, the landscape of municipalities is changing rapidly mainly due to mergers. The Swiss Municipality Merger Tool (SMMT) automatically detects these mutations and maps municipalities of an old state to municipalities of a new state. The aim of this vignette is to illustrate how to use the functionality of the SMMT.

This figure shows the decrease in municipalities over time:

This figure shows the mutations for the decade 2010-2019:

Source: https://www.atlas.bfs.admin.ch/

How To

Setup

Download & unpack the Swiss municipality inventory from the Federal Statistical Office website.

path_inventory_xml <- download_municipality_inventory(path = getwd())

Import the inventory into the workspace

mutations_object <- import_CH_municipality_inventory(file_path = path_inventory_xml)
mutations        <- mutations_object$mutations

# Alternative: Use a local available version (e.g. Version from January 1st, 2018):
file_path_inventory_xml <- "path/to/eCH0071_180101.xml"
mutations_object <- import_CH_municipality_inventory(file_path = file_path_inventory_xml)
mutations        <- mutations_object$mutations

Get Mapping Table

Define the old state and the new state. Example:

old_state <- as.Date("1961-01-01")
new_state <- as.Date("1963-01-01")

Get mapping table

mapping_object <- map_old_to_new_state(mutations, old_state, new_state)
mapping_table  <- mapping_object$mapped

Excerpt of mapping table:

bfs_nr_new	name_new	bfs_nr_old	name_old
4021	Baden	4021	Baden
4021	Baden	4025	Daettwil

If of relevance, use the information about municipalities which could not be mapped (e.g. due to secessions). For example, if you need to exclude these elements from a dataset.

Definitions

Spatial reference (German: Raumbezug): Set of municipalities at a given point in time. For example, the spatial reference of the Federal Population census year 2000 is the 5 December 2000.

Further information