update_nuvi_maps.sh

#!/usr/bin/env bash
set -euo pipefail

# --------------------------------------------------------------------
# Configuration
# --------------------------------------------------------------------
# Directory where temporary files will be stored
WORKDIR="${HOME}/garmin_map_update"
mkdir -p "${WORKDIR}"

# Destination mount point of the Nuvi device
# Change this to match your system
GARMIN_MOUNT="/media/garmin"         # Linux
# GARMIN_MOUNT="/Volumes/Garmin"     # macOS

# OSM extract URLs (central/eastern US + Canada)
# Sources: https://download.geofabrik.de/
OSM_URLS=(
    "https://download.geofabrik.de/north-america/us/western-oregon-latest.osm.pbf"
    "https://download.geofabrik.de/north-america/us/midwest-latest.osm.pbf"
    "https://download.geofabrik.de/north-america/us/eastern-latest.osm.pbf"
    "https://download.geofabrik.de/north-america/canada/ontario-latest.osm.pbf"
    "https://download.geofabrik.de/north-america/canada/quebec-latest.osm.pbf"
)

# Output folder inside the Nuvi where Garmin expects map files
GARMIN_MAP_DIR="${GARMIN_MOUNT}/Garmin/Map"

# --------------------------------------------------------------------
# Helper functions
# --------------------------------------------------------------------
log() {
    echo -e "[\e[32m$(date +'%H:%M:%S')\e[0m] $*"
}

error_exit() {
    echo -e "\e[31mERROR: $*\e[0m" >&2
    exit 1
}

# --------------------------------------------------------------------
# Main steps
# --------------------------------------------------------------------
log "Starting Garmin Nuvi map update..."

# Ensure the device is mounted
[[ -d "${GARMIN_MOUNT}" ]] || error_exit "Garmin mount point not found: ${GARMIN_MOUNT}"

# Create map directory if it doesn't exist
mkdir -p "${GARMIN_MAP_DIR}"

# Download each OSM extract (skip if already present)
for url in "${OSM_URLS[@]}"; do
    filename=$(basename "${url}")
    dest="${WORKDIR}/${filename}"
    if [[ -f "${dest}" ]]; then
        log "Found existing ${filename}, skipping download."
    else
        log "Downloading ${filename} ..."
        wget -q --show-progress -O "${dest}" "${url}"
    fi
done

# Convert each .pbf into Garmin .img using gpsbabel
for pbf in "${WORKDIR}"/*.osm.pbf; do
    base=$(basename "${pbf}" .osm.pbf)
    img="${WORKDIR}/${base}.img"

    if [[ -f "${img}" ]]; then
        log "Image ${base}.img already exists, skipping conversion."
        continue
    fi

    log "Converting ${base}.osm.pbf → ${base}.img ..."
    gpsbabel -i osm -f "${pbf}" -o garminimg -F "${img}" \
        --garminimg-zoom-levels=0,10 \
        --garminimg-wpt-plane=off \
        --garminimg-veh-attr=on \
        --garminimg-route=off \
        --garminimg-attr-limit=2
done

# Copy the .img files to the Nuvi
log "Copying .img files to the device..."
cp -v "${WORKDIR}"/*.img "${GARMIN_MAP_DIR}/"

# Optional: clean up old map files (delete non‑generated .img files)
# Uncomment if you want a clean map folder each run:
# find "${GARMIN_MAP_DIR}" -type f -name "*.img" ! -path "${WORKDIR}/*.img" -delete

log "Map update complete. Safely eject your Nuvi device."