Flutter + Firebase 开发流水账


指纹解锁APP -> 等待APP跳转到下一个界面 -> 点击“Start an order” -> 等待APP跳转到下一个界面 -> 选择预约地点 -> 等待APP加载数据 -> 选择日期时间 -> 等待APP加载数据 -> 将早饭/中饭/晚饭加入购物车 -> 等待APP跳转到下一个界面 -> 结算购物车 -> 等待确认邮件


寒假的时候闲来无事,就和另外两位CS系的同学,用Flutter和Firebase替学校的Dining Service开发了一款更加简单易用的预约软件,准备在春天投放使用,改善一下大家的预约订餐体验。比起原有的APP,新开发的APP主要有以下一些方面的改进:

  • 改用Google Account一次验证登录用户,省去了每次解锁APP的流程
  • 日期、地点和时间选择全部放在同一界面上,前端数据实时刷新,方便用户一键预约
  • 在就餐地点部署PROX读卡设备,用户点单后可以直接刷卡进入
  • 新增历史订单查看和取消功能


Continued reading >

Mapping Qing Relay Stations

The beta stage site is here.

During the Qing dynasty, the large network of postal and military stations, connecting the ruling kernel with China proper, Manchuria, Mongolia, Sinkiang, and Tibet, were venues of information and military logistics for monitoring the empire, and also routes which officials, scholars, merchants traveled. My recent project has been one of retracing these routes and transforming them into GIS databases. I will give a very brief technical overview of the backstage process here, and more blogs concerning specific routes will be posted in the coming months(most likely in Chinese).

Data Aggregation

The main primary source that I used was The Jiaqing Administrative Code of the Qing Dynasty (Jiaqing Huidian 嘉慶會典). My initial plan was to extract the information using OCR and then geocoding the raw data with a Google API. However, most of the OCR software that I tried was quite abysmal at discerning Chinese characters that were oriented vertically. I tinkered around a lot with various software parameters and have even thought of writing my own OCR specialized for this purpose but to no avail. In the end, I decided that for my data size, it was faster to have a flawed OCRed result and then eyeball the data for corrections. Geocoding was also pretty challenging: the Google API could only identify place names that had not changed since the Qing period and I had to do a lot of textual research in travel logs and gazettes to uncover the present-day location. For anyone interested, Xiao fang hu zhai yu di cong chao (小方壺齋輿地叢鈔) is a good source to look into.

Continued reading >


无趣的RMQ-ST 模板。

[BZOJ1003] 物流运输