貌似當前A*都是在畫好的方格內實現最短路徑搜索，百度、騰訊、高德地圖可以在存在道路的區域實現路徑導航。如何實現在地圖上沒有道路的區域，例如景區、商場、偏遠山區自定義路徑並查找出最短路徑？
通過切圖工具與A*代碼的組合使用，初步實現了這功能。基本思路是首先在圖片上畫好路徑，然後用切圖工具將圖片矢量化，將矢量信息配準到地圖，最後將計算出的最短路徑映射到地圖，並在地圖上顯示出來。目前的缺點是轉彎處比較生硬不平滑、路徑沒有方向指示、現在僅支持騰訊地圖。以後慢慢解決。
（截止今天20190131工具還沒有升級，近期將完成更新，敬請關注。感謝 @大臉團團 的支持！）
上面黑圖是輔助測試用的。
上面的6個多邊形障礙物信息，由切圖工具輸出，信息太多，應該以後可以優化：
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