Show HN: Shapefile viewer that asks which datum when the .prj is missing

AI Digest

文章介绍一个Shapefile查看器工具，当缺少.prj文件时会提示选择坐标系，特别强调日本数据因坐标系差异可能导致464米偏移问题。

This tool converts Shapefiles to GeoJSON, prompting datum selection when .prj is missing. Japanese data using legacy Tokyo Datum may shift 464m without .prj files.

Key points

• 工具可将Shapefile转换为GeoJSON并处理缺失.prj文件的坐标系选择 Converts Shapefiles to GeoJSON with datum selection when .prj is missing
• 日本旧数据使用东京坐标系导致与现代坐标系出现464米偏差 Japanese legacy data using Tokyo Datum may shift 464m without .prj
• 转换时需包含.shp/.shx/.dbf核心文件，.prj可自动识别坐标系 Requires .shp/.shx/.dbf files; .prj auto-detects coordinate system
• 无.prj时需手动选择datum，不同坐标系数值相似但位置差异显著 Manual datum selection needed without .prj, with visually similar coordinates
• 浏览器内完成转换无需安装软件，数据不上传服务器 Browser-based conversion without installation or data upload

Takeaway: 坐标系选择直接影响空间数据准确性，尤其对日本历史数据处理至关重要。 / Datum selection critically affects spatial accuracy, especially for Japanese historical data.

Why it matters 解决空间数据坐标系歧义问题，对地理分析有实际操作价值。