CDT Journal

A personal trail journal app for my 2024 Continental Divide Trail thru-hike — ~3,000 miles from the Canadian border in Montana to the New Mexico/Mexico border. While hiking I kept a journal, tracked campsites, sent GPS messages home, and took a lot of photos. This app is my attempt to pull all of that together into one place.

Built with Next.js 15, TypeScript, PostgreSQL, and D3.js.

Features

• Interactive map — D3.js visualization showing daily trail segments, campsites, Garmin message locations, and geotagged photos across all five CDT states. Includes a zoomable explore panel to jump to any day's trail segment directly from the map.
• Journal entries — Create, read, and edit daily entries linked to a specific date and trail leg. Each entry page includes a mini-map of that day's route.
• Photo album — Full photo gallery with lightbox, sourced from photos taken on trail.
• Calendar view — Browse entries by date.
• Elevation contours — Topographic contour lines on the map generated from DEM raster files via a Python preprocessing script.
• Authentication — Password-protected journal routes (NextAuth v5, bcrypt).

Tech Stack

Layer	Choice
Framework	Next.js 15 (App Router, React Server Components, Server Actions)
Language	TypeScript
Styling	Tailwind CSS v4 + DaisyUI
Database	PostgreSQL on Neon
Map	D3.js (geoConicConformal projection)
Photos	react-photo-album + yet-another-react-lightbox
Auth	NextAuth v5 (Credentials provider)
Validation	Zod
Package manager	pnpm

Data Model

• dates — one row per day on trail
• entries — journal text, linked to a date and state
• legs — GPS trail segments (from CalTopo exports), linked to a date; include coordinates and mileage
• photos — images with EXIF lat/lon, linked to a date
• users — authentication only

Getting Started

Prerequisites

• Node.js 20+
• pnpm
• A PostgreSQL database (the app uses Neon)

Environment variables

Create a .env file at the project root:

AUTH_SECRET=
POSTGRES_URL=
DATABASE_URL=
PGHOST=
PGUSER=
PGPASSWORD=
PGDATABASE=

Install and run

pnpm install
pnpm dev        # development server (Turbopack)
pnpm build      # production build
pnpm start      # start production server
pnpm lint       # ESLint

Contour Generation

Topographic contour lines are pre-generated from DEM raster files and saved to public/contours.geojson. To regenerate:

1. Export trail legs from the running dev server:

   curl http://localhost:3000/api/legs > scripts/trail_legs.geojson

2. Drop .tif files into scripts/dem/
3. Run the script:

   python3 scripts/generate_contours.py

The script clips each raster to a 30-mile corridor around the trail before extracting contours, which keeps the output file size manageable. Requires rasterio, scikit-image, numpy, and optionally shapely for the trail buffer clipping.

Data Sources

• Trail segments — drawn in CalTopo based on campsite locations, exported as GeoJSON
• Garmin messages & campsites — exported from Garmin Explore, parsed to extract date, coordinates, and message content
• Photos — EXIF metadata extracted with exifr to get GPS coordinates and timestamps
• Elevation data — USGS 1/3 arc-second DEM tiles