ALMR Terrain Coverage Tiles

This repository hosts slippy-map terrain coverage tiles (XYZ format) for the Alaska Land Mobile Radio (ALMR) network, as well as a lightweight Leaflet viewer.

Repository Contents

• index.html: A simple, standalone Leaflet-based map viewer to preview the hosted tiles locally or online.
• almr_tiles/: The directory containing generated coverage tiles structured as {z}/{x}/{y}.png.
• .nojekyll: Prevents GitHub Pages from ignoring directories or files (if any start with underscores or other Jekyll-restricted patterns).

Tile Generation & Color Scale

These tiles are generated in the sister repository almr-coverage by parsing Pathloss 6 KMZ exports, vectorizing signal bands, and rendering them into slippy-map tiles.

The coverage layers map to the following signal strength thresholds:

Color	Hex	Range	Signal Class / Quality
Red	#e31a1c	$\ge -50\text{ dBm}$	Strongest (Excellent indoor/handheld)
Orange	#ff7f00	$-50$ to $-65\text{ dBm}$	Strong
Green	#33a02c	$-65$ to $-80\text{ dBm}$	Good (Reliable portable coverage)
Blue	#1f78b4	$-80$ to $-95\text{ dBm}$	Moderate (Reliable vehicle coverage)
Purple	#984ea3	$-95$ to $-116\text{ dBm}$	Fringe (Marginal voice coverage)

Signal levels below $-116\text{ dBm}$ are considered out of range and are not rendered (transparent).

---

Local Development & Testing

You can spin up a local server to view the Leaflet interface and test tile loading:

python3 -m http.server 8000

Once running, visit:

• Viewer: http://localhost:8000/index.html
• Tile Endpoint: http://localhost:8000/almr_tiles/{z}/{x}/{y}.png

---

Registering Tiles in CalTopo

Once hosted (e.g. via GitHub Pages), you can overlay this layer directly onto any CalTopo map:

1. Open your CalTopo map workspace.
2. In the left sidebar, click Add > Custom Source.
3. Configure the source:
   • Name: ALMR Terrain Coverage
   • Type: Tile
   • URL Template: https://<your-username>.github.io/<your-repo>/almr_tiles/{z}/{x}/{y}.png
     • (Note: Ensure the hosting server sends the Access-Control-Allow-Origin: * header for CORS, which GitHub Pages does by default).
   • Max Zoom: 12
4. Click Save. You can now toggle the ALMR coverage overlay on any map canvas.