https://gist.github.com/DaisukeMiyazaki/4293e05627ecae17b23dd8b234a29a12

This is a Google Apps Script (GAS) tool that automatically calculates the travel route (train/walk) to an event when you add it to Google Calendar, and adds a “Travel to…“ event to your calendar.

Features

1. Automatic Route Calculation
   • Reads the “Location” of the event and searches for a route using the Google Maps API.
   • Automatically determines the starting point from “Home (default)” or “Location of the previous event (if events are back-to-back)”.
2. Arrive 15 Minutes Early
   • Schedules travel time so that you arrive at the destination 15 minutes before the event starts.
3. Detailed Route Guidance
   • Automatically adds the train time, line name, transfer station, and fare (if available) to the Description field of the calendar event.
4. Automatic Return Route
   • Automatically creates a travel plan (Travel to Home) to return home after the last event of the day ends.
5. Duplicate Prevention
   • Does not double-register if a travel plan has already been created.

Setup Instructions

This tool requires no server and runs on Google Apps Script.

1. Create a Project

1. Access Google Apps Script (script.google.com) in your browser.
2. Create a “New Project”.

2. Install the Code

1. Copy the contents of calendar_auto_route.js from this repository.
2. Paste everything into Code.gs in the GAS editor.

3. Change Settings

Rewrite the constants at the beginning of the code to match your environment.

const CALENDAR_ID = "primary"; // Leave as is if using your own calendar
const HOME_LOCATION = "Ofuna Station, Kamakura"; // Address of your home or nearest station

4. Enable Service

To use Google Maps functions, the following steps may be required (currently, the standard Maps class is often used, so additional settings are often unnecessary, but just in case).

• Click the “+” button in “Services” on the left menu -> Add “Google Maps Service” if available (usually not required).

5. Trigger Settings (Automation)

1. Click the clock icon (Trigger) on the left menu.
2. Click the “Add Trigger” button.
3. Set as follows and save:
   • Function to run: onCalendarChange
   • Event source: From calendar
   • Event type: Event updated
4. You will be asked for permission to access your Google account when saving, so “Allow” it.
   • If “This app is not verified by Google” appears, click “Advanced” -> “Go to (Project Name)” and allow it.

Usage

1. Add an event to Google Calendar. Be sure to fill in the “Location” field.
2. After a few seconds to tens of seconds, a new event called “Travel to [Event Name]” will be automatically added immediately before that event.
3. Click on the added event to check “what time to catch the train” in the details field.

Notes

• When the trigger fires, scan events from today to 14 days later.
• Find events that have a “Location” and do not have “Travel to” immediately before them, and process them.
• Route search uses Maps.newDirectionFinder() (Transit Mode).
• Outbound search uses .setArrive(start - 15min), return uses .setDepart(end).