flutter pub add google_polyline_algorithm根據套件公開資料產生的選型評估，僅供參考。
Google 的 Polyline 編碼演算法的 Dart 實作，用於將緯度與經度座標壓縮為緊湊的字串格式。這種損失性壓縮可減少地圖路徑的資料大小，非常適合在地理定位應用中進行高效傳輸與儲存。此套件支援所有主要平台，包含 Android、iOS、Web、macOS、Windows 與 Linux。讓開發者能以最小的開銷編碼與解碼折線，同時維持大多數地圖使用情境所需的足夠準確度。
以下為關聯原始碼儲存庫的 README 原文快照，最新內容請造訪原始碼儲存庫。
Dart implementation of Googles Polyline Encoding lossy compression Algorithm.
This package adds following methods to work with Googles Polyline Encoding Algorithm:
encodePoint(num current, {num previous = 0, int accuracyExponent = 5}) encodes a single coordinate
encodePolyline(List<List<num>> coordinates, {int accuracyExponent = 5}) encodes a list of coordinates into an encoded polyline stirng
decodePolyline(String polyline, {int accuracyExponent = 5}) decodes an encoded polyline string into a list of coordinates
import 'package:google_polyline_algorithm/google_polyline_algorithm.dart';
final coord = encodePoint(-179.9832104);
print(coord);
// output is `~oia@'
final coords = encodePolyline([
[38.5, -120.2],
[40.7, -120.95],
[43.252, -126.453],
]);
print(coords);
// output is `_p~iF~ps|U_ulLnnqC_mqNvxq`@'
final polyline = decodePolyline('_p~iF~ps|U_ulLnnqC_mqNvxq`@');
print(polyline);
// output is [[38.5, -120.2],[40.7, -120.95],[43.252, -126.453],]