Historical municipal meshes
In brazilmaps: Brazilian Maps from Different Geographic Levels

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.align = "center"
)

library(brazilmaps)

Inventory

brmap_editions() is the authoritative installed inventory. It records feature counts, compressed file sizes, checksums, processing metadata and exact IBGE source URLs.

inventory <- brmap_editions()
inventory[c("year", "n_features", "md5")]

Every row represents a bundled milestone. Within each consecutive run with the same municipality count, the package keeps only the latest official edition. This preserves every change in the number of municipalities while leaving more space for less aggressive geometry simplification.

Select an edition

mesh_2000 <- get_brmap("municipality", year = 2000)
mesh_2010 <- get_brmap("municipality", year = 2010)
mesh_current <- get_brmap("municipality")

c(
  `2000` = nrow(mesh_2000),
  `2010` = nrow(mesh_2010),
  current = nrow(mesh_current)
)

An unavailable year produces an informative error instead of silently substituting another edition.

Compare a state through time

go_2000 <- get_brmap(
  "municipality", year = 2000, filters = list(state = 52)
)
go_current <- get_brmap("municipality", filters = list(state = 52))

plot_brmap(go_2000) +
  ggplot2::labs(title = "Municipal mesh of Goiás — 2000")

The geometry is simplified consistently for visualization, retaining 5% of weighted Visvalingam vertices. Do not calculate legal areas or cadastral boundaries from these objects.

Hierarchy and historical codes

state_code and region_code are stored with each edition. Immediate, intermediate, microregion and mesoregion fields are attached from the installed current DTB when a municipality code can be matched. Consequently, filtering a historical edition by a current regional division is a present-day classification of the historical geometry, not a reconstruction of that division in the selected year.

All objects are returned in SIRGAS 2000 (EPSG:4674), including early meshes whose source datum was SAD69.