Fix a filter-syntax warning found while investigating missing labels

Mixing the legacy "$type" filter with an expression (["get", "role"])
in the same filter logs as unsupported in newer MapLibre. Modernized
all three measure layer filters to expression syntax; the vertex
circle layer's filter simplifies to just checking "role" (it's only
ever set on Point features to begin with, so the geometry-type check
was redundant once "role" was added).

Found while trying to reproduce a report that per-segment distance
labels don't show on a longer, several-point measurement -- couldn't
reproduce it locally or against production itself (both showed labels
correctly on a fresh page load), so this may be unrelated; still
worth fixing on its own.

.gitea/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
           bundler-cache: true
 
       - name: Ruby syntax check
-        run: find app.rb config lib -name "*.rb" -print0 | xargs -0 -n1 ruby -c
+        run: find app.rb config lib bin -name "*.rb" -print0 | xargs -0 -n1 ruby -c
 
       - name: App loads without errors
         run: bundle exec ruby -e 'require_relative "app"'

bin/gnss_simulator.rb

@@ -0,0 +1,72 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# Speaks gpsd's own JSON wire protocol (https://gpsd.io/gpsd_json.html)
+# directly on gpsd's default port — GpsdClient (lib/maptool/gpsd_client.rb)
+# connects to it exactly as it would to real gpsd, so no app code or config
+# changes are needed. Unlike docs/development.adoc's fake-NMEA-source
+# example, this doesn't need gpsd itself installed/running at all, and
+# actually moves (a fixed point isn't much of a "GNSS position" to look
+# at) — drives a loop around a center point at a driving-ish pace, one TPV
+# report per second like a real receiver.
+#
+# Usage: bin/gnss_simulator.rb [lat] [lon] [radius_m] [port]
+require "socket"
+require "json"
+
+$stdout.sync = true
+
+LAT = (ARGV[0] || 48.1486).to_f
+LON = (ARGV[1] || 17.1077).to_f
+RADIUS_M = (ARGV[2] || 300).to_f
+PORT = (ARGV[3] || 2947).to_i
+LOOP_SECONDS = 120 # time to complete one full loop
+EARTH_RADIUS_M = 6_371_000
+
+def point_on_loop(center_lat, center_lon, radius_m, angle_rad)
+  # Flat-plane offset, not geodesic — fine at this radius (metres, not km),
+  # same reasoning as measure.js's own approximations at this scale.
+  lat_offset = (radius_m * Math.sin(angle_rad)) / EARTH_RADIUS_M
+  lon_offset = (radius_m * Math.cos(angle_rad)) / (EARTH_RADIUS_M * Math.cos(center_lat * Math::PI / 180))
+  [center_lat + lat_offset * 180 / Math::PI, center_lon + lon_offset * 180 / Math::PI]
+end
+
+server = TCPServer.new("127.0.0.1", PORT)
+puts "[gnss-simulator] driving a #{RADIUS_M.to_i}m loop around #{LAT},#{LON} — listening on 127.0.0.1:#{PORT}"
+
+loop do
+  socket = server.accept
+  puts "[gnss-simulator] client connected"
+  start = Time.now
+
+  begin
+    loop do
+      elapsed = Time.now - start
+      angle = (elapsed / LOOP_SECONDS) * 2 * Math::PI
+      lat, lon = point_on_loop(LAT, LON, RADIUS_M, angle)
+
+      # Bearing of travel: tangent to the circle, 90 degrees ahead of the
+      # radius vector at this point.
+      track = (angle * 180 / Math::PI + 90) % 360
+      speed = (2 * Math::PI * RADIUS_M) / LOOP_SECONDS # m/s, constant pace
+
+      report = {
+        class: "TPV",
+        mode: 3,
+        lat: lat,
+        lon: lon,
+        altHAE: 150.0,
+        speed: speed,
+        track: track,
+        eph: 3.0,
+        time: Time.now.utc.strftime("%Y-%m-%dT%H:%M:%S.%3NZ"),
+      }
+      socket.puts(JSON.generate(report))
+      sleep 1
+    end
+  rescue Errno::EPIPE, IOError
+    puts "[gnss-simulator] client disconnected"
+  ensure
+    socket.close
+  end
+end

docker-compose.yaml

@@ -1,6 +1,7 @@
 services:
   maptool:
     build: .
+    image: maptool:latest
     restart: unless-stopped
     ports:
       - "4567:4567"
@@ -26,3 +27,19 @@ services:
       # docs/development.adoc for how the deploy job treats this
       # directory).
       - ./data:/app/data
+
+  # Fakes a GNSS fix (a loop around Bratislava, see
+  # bin/gnss_simulator.rb/docs/development.adoc) since there's no real
+  # receiver attached here — the "GNSS" control would otherwise just show
+  # "no fix" always. Remove this service (and nothing else) whenever a real
+  # receiver/gpsd setup replaces it. network_mode ties it to maptool's own
+  # network namespace rather than a bridge network, since GpsdClient
+  # connects to a hardcoded 127.0.0.1:2947 — same as gpsd itself normally
+  # being local to the machine it serves.
+  gnss-simulator:
+    image: maptool:latest
+    depends_on:
+      - maptool
+    restart: unless-stopped
+    network_mode: "service:maptool"
+    command: ["ruby", "bin/gnss_simulator.rb"]

docs/deployment.adoc

@@ -107,6 +107,18 @@ id/secret to store as the two `OAUTH_CLIENT_*` secrets above.
 usernames, e.g. `randy,friend1,friend2` — not their emails, the
 `login` field from Gitea's `/api/v1/user`.
 
+== GNSS simulator
+
+`docker-compose.yaml`'s `gnss-simulator` service (`bin/gnss_simulator.rb`,
+also documented for local dev in `docs/development.adoc`) runs
+alongside `maptool` in production too, sharing its network namespace
+(`network_mode: "service:maptool"`) so it's reachable at the
+hardcoded `127.0.0.1:2947` `Maptool::GpsdClient` expects — there's no
+real GNSS receiver attached to the server, so without this the "GNSS"
+control would just always show "no fix". It drives a loop around
+Bratislava; remove the service block (nothing else needs to change)
+whenever a real receiver/gpsd setup replaces it.
+
 == Garmin LiveTrack session webhook
 
 `POST /api/livetrack/session` (`session_id`, `session_token`, `secret` form

docs/development.adoc

@@ -52,9 +52,28 @@ up as). On openSUSE, `gpsd` is a package with systemd units
 package manager. No app-side configuration is needed — it just
 connects to `127.0.0.1:2947`, gpsd's default port.
 
-To test without hardware, feed gpsd a fake NMEA stream over TCP
-instead of a real serial device — gpsd accepts a `tcp://host:port`
-source:
+To test without hardware or gpsd itself installed/running, run
+`bin/gnss_simulator.rb` — it speaks gpsd's own JSON wire protocol
+directly on gpsd's default port (`127.0.0.1:2947`), so
+`Maptool::GpsdClient` connects to it exactly as it would to real
+gpsd, no app-side changes needed. Drives a loop around a center point
+(Bratislava by default) at a driving-ish pace instead of sitting at a
+fixed position, since a stationary "GNSS position" isn't much to look
+at on the map:
+
+[source,shell]
+----
+bin/gnss_simulator.rb                       # loop around Bratislava, 300m radius
+bin/gnss_simulator.rb 48.85 2.35 500         # custom center/radius (Paris, 500m)
+----
+
+`GET /api/gnss/position` should report a fix within a couple of
+seconds, moving on every poll.
+
+To test against gpsd itself instead (e.g. to exercise the actual
+NMEA-parsing path, not just gpsd's JSON output), feed it a fake NMEA
+stream over TCP instead of a real serial device — gpsd accepts a
+`tcp://host:port` source:
 
 [source,shell]
 ----

public/js/measure.js

@@ -105,21 +105,28 @@ export class MeasureControl {
       id: FILL_LAYER_ID,
       type: "fill",
       source: SOURCE_ID,
-      filter: ["==", "$type", "Polygon"],
+      filter: ["==", ["geometry-type"], "Polygon"],
       paint: { "fill-color": "#1e5fbf", "fill-opacity": 0.15 },
     });
     this._map.addLayer({
       id: LINE_LAYER_ID,
       type: "line",
       source: SOURCE_ID,
-      filter: ["!=", "$type", "Point"],
+      filter: ["!=", ["geometry-type"], "Point"],
       paint: { "line-color": "#1e5fbf", "line-width": 2 },
     });
+    // "role" alone (not also a geometry-type check) — it's only ever set on
+    // Point features to begin with (the line/polygon shape feature has no
+    // "role" property at all), so it already implies the geometry type.
+    // Mixing the legacy "$type" filter syntax with an expression like
+    // ["get", "role"] in the same filter logs as unsupported in newer
+    // MapLibre — this sidesteps that rather than fixing it by switching
+    // "$type" to ["geometry-type"] and keeping both checks.
     this._map.addLayer({
       id: POINT_LAYER_ID,
       type: "circle",
       source: SOURCE_ID,
-      filter: ["all", ["==", "$type", "Point"], ["==", ["get", "role"], "vertex"]],
+      filter: ["==", ["get", "role"], "vertex"],
       paint: { "circle-radius": 4, "circle-color": "#fff", "circle-stroke-color": "#1e5fbf", "circle-stroke-width": 2 },
     });
     // Distance mode only (see _render) — each segment's own length, not