Traffic v0.9

Features in full

ATAK can already display an online tile source, and a MOBAC source can declare a refresh interval. Two things stop that from producing a live overlay. The interval is only honored while the map is being drawn, so a device that pans stays current and a device sitting on a desk silently goes stale -- which is the state an operator is usually in when they want to read traffic. And a composited multi-layer source is built with no refresh interval at all, so the one arrangement that puts traffic over an operator's own base map is the one arrangement that cannot refresh.

This plugin owns its own overlay layer and drives the refresh itself.

Capabilities

• Traffic drawn above the operator's chosen base map, which stays visible underneath. Imagery, topo or vector -- the overlay does not replace it.
• Refreshes on a wall clock while the map is untouched, at an interval the operator selects (15 seconds to 10 minutes).
• Holds while the screen is off, and refreshes immediately on wake. Nothing can render with the display off, so refreshing then would spend battery to no purpose; what matters is being current the moment the device is picked up. The status says so explicitly when tiles arrived because the device was woken, rather than leaving the operator to infer it from a recent timestamp.
• Manual refresh that takes effect at once rather than at the next interval.
• A status line reporting when tiles genuinely last arrived, read from the tile cache rather than from the plugin's own timer, so a stalled network shows as a timestamp that stops moving rather than one that keeps ticking over a frozen picture.
• One tap on and off, from the plugin pane, with the state shown as a color-coded ON or OFF rather than buried in a sentence.
• Highway shields drawn above the traffic colors, so a route number stays readable where the traffic line would otherwise cover it.

Road incidents (511), new in 0.7

• Crashes, closures, lane closures, road work, hazards, vehicle fires, chain control, weather and message signs from every US state's traveler information system, drawn as icons. No road lines: traffic flow comes from the traffic overlay above.
• The operator picks the states they care about; the first run offers the state they are in.
• Each type can be switched off, drawn only past a chosen zoom, and limited to what is in view or a radius around the operator or the map center.
• Tapping an incident opens its details, which keep updating while open: what, where, the reporting agency, when it was reported and last updated, responding units where the agency publishes them (California Highway Patrol), and message signs drawn as the sign reads.
• Refreshes every 15 seconds while the screen is on.

Equipment required

Android device supported by ATAK-CIV 5.6, 5.7 or 5.8. A network connection while the overlay is in use. Traffic is live data and has no meaningful offline mode -- cached tiles are, by definition, old traffic. Negligible storage: tiles land in ATAK's existing imagery cache; road incidents are held in a small per-session database under ATAK's tools directory, replaced each time the plugin starts.

Works with

Any Android device supported by ATAK. No additional or external hardware, no sensors, no peripherals.

Network and security

(This is important for ATO, networking, and other security concerns)

Outbound TCP 443 (HTTPS) only, and only while the operator has the overlay or the road incidents turned on and the device screen is awake.

The plugin streams map tiles from a Google tile endpoint, mt1.google.com. This is an undocumented, unauthenticated endpoint -- no API key is used or required. Requests carry no credentials and no device identity.

What leaves the device is the set of tile coordinates covering the visible map area, at the operator's selected refresh interval. Tile coordinates are derived from the map viewport, so the operator's area of interest is inferable by the tile provider at the resolution of a map tile. This is inherent to any streamed tile source and is stated here so it is not a surprise.

Traffic is requested at whatever interval the operator selects, default 60 seconds. Turning the overlay off, or the screen off, stops all traffic immediately. Highway shields come from the same Google endpoint, as a second tile layer over the same area.

Road incidents (511) come from takwerx's own server, cams.takwerx.org, path /traffic511/. The device asks it for a small index every 15 seconds and for the file of each state the operator picked when that file has changed (conditional GET, If-Modified-Since). Requests carry no credentials and no device identity; what the server can infer is which states were picked. The server gathers the data from each state's public traveler information system; the device never contacts a state agency itself.

No inbound ports. No listening sockets. No traffic to or from the TAK server, and no CoT is generated or consumed. With the overlay and the road incidents off the plugin makes no network calls at all.

Tiles are cached by ATAK's own imagery cache, in the standard imagecache location, and are subject to ATAK's cache management.

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