Use local PMTiles basemap

scripts/extract-mandan-pmtiles.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [[ $# -lt 1 || $# -gt 2 ]]; then
+  echo "Usage: $0 PROTOMAPS_SOURCE_URL [OUTPUT_FILE]" >&2
+  exit 2
+fi
+
+if ! command -v pmtiles >/dev/null 2>&1; then
+  echo "The pmtiles CLI is required: https://docs.protomaps.com/pmtiles/cli" >&2
+  exit 1
+fi
+
+source_url=$1
+output_file=${2:-tiles/mandan.pmtiles}
+
+if [[ -e "$output_file" ]]; then
+  echo "Refusing to overwrite existing file: $output_file" >&2
+  exit 1
+fi
+
+# Mandan city plus a modest margin for labels and roads. PMTiles extracts
+# tile-aligned bounds, so the resulting archive includes some nearby context.
+pmtiles extract \
+  "$source_url" \
+  "$output_file" \
+  --bbox=-101.05,46.74,-100.75,46.93
+
+pmtiles show "$output_file"