From ff77bc31e776ce72e509cc22d194c9a7cf45cec0 Mon Sep 17 00:00:00 2001
From: Chandler Swift <chandler@chandlerswift.com>
Date: Thu, 1 Feb 2024 01:10:18 -0600
Subject: [PATCH] Add Viarail layer

---
 layers/index.js            |  5 +++++
 layers/viarail/get_data.py | 43 ++++++++++++++++++++++++++++++++++++++
 layers/viarail/layer.js    | 26 +++++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100755 layers/viarail/get_data.py
 create mode 100644 layers/viarail/layer.js

diff --git a/layers/index.js b/layers/index.js
index 109133c..09b0ef9 100644
--- a/layers/index.js
+++ b/layers/index.js
@@ -4,6 +4,7 @@ import Stamen from 'ol/source/Stamen.js';
 
 import chandlerLayer from './chandler/layer.js';
 import amtrakLayer from './amtrak/layer.js';
+import viarailLayer from './viarail/layer.js';
 import arenasLayer from './nhl-arenas/layer.js';
 import bikepackingLayer from './bikepacking/layer.js';
 import chains from './chains/index.js';
@@ -68,6 +69,10 @@ const layerCategories = [
                 name: "Amtrak Routes",
                 layer: amtrakLayer,
             },
+            {
+                name: "Via Rail Routes",
+                layer: viarailLayer,
+            },
             {
                 name: "NHL Arenas",
                 layer: arenasLayer,
diff --git a/layers/viarail/get_data.py b/layers/viarail/get_data.py
new file mode 100755
index 0000000..38c122f
--- /dev/null
+++ b/layers/viarail/get_data.py
@@ -0,0 +1,43 @@
+#!/usr/bin/python3
+
+import csv
+import io
+import json
+import zipfile
+import urllib.request
+
+shapes = {}
+
+# https://stackoverflow.com/a/5711095
+resp = urllib.request.urlopen("https://www.viarail.ca/sites/all/files/gtfs/viarail.zip")
+with zipfile.ZipFile(io.BytesIO(resp.read())).open('shapes.txt') as f:
+    reader = csv.DictReader(io.TextIOWrapper(f))
+    for row in reader:
+        # they look like they're probably all in order, but the spec doesn't
+        # actually say that they have to be, so we're going to bucket them by
+        # route and then sort each bucket's contents to be on the safe side.
+        # It's not that much data, and I don't run this download frequently, so
+        # the extra CPU cost shouldn't be too outrageous :)
+        if row['shape_id'] not in shapes:
+            shapes[row['shape_id']] = []
+        shapes[row['shape_id']].append(row)
+
+geojson = {
+    "type": "FeatureCollection",
+    "features": [],
+}
+
+for _, shape in shapes.items():
+    shape.sort(key=lambda c: int(c['shape_pt_sequence']))
+    geojson['features'].append({
+            "type": "Feature",
+            "geometry": {
+                "type": "LineString",
+                "coordinates": [
+                    [float(l['shape_pt_lon']), float(l['shape_pt_lat'])] for l in shape
+                ]
+            },
+        })
+
+with open('data.geojson', 'w') as f:
+    f.write(json.dumps(geojson))
diff --git a/layers/viarail/layer.js b/layers/viarail/layer.js
new file mode 100644
index 0000000..63b4d99
--- /dev/null
+++ b/layers/viarail/layer.js
@@ -0,0 +1,26 @@
+import VectorLayer from 'ol/layer/Vector';
+import {Vector as VectorSource} from 'ol/source.js';
+import GeoJSON from 'ol/format/GeoJSON.js';
+
+import {Style, Stroke} from 'ol/style.js';
+
+import url from './data.geojson?url'; // TODO: remove `?url`?
+
+const colors = '255,0,0'; // "Canadian red"...is just red? https://en.wikipedia.org/wiki/National_colours_of_Canada#Reproduction
+
+const vectorLayer = new VectorLayer({
+    source: new VectorSource({
+        url: url,
+        format: new GeoJSON,
+    }),
+    style: function(feature, resolution){
+        return new Style({
+            stroke: new Stroke({
+                color: `rgba(${colors},${Math.min(1, Math.pow(resolution/10, 1/4))})`,
+                width: 10/Math.pow(resolution, 1/4),
+            })
+        });
+    },
+});
+
+export default vectorLayer;