Nice work and nice writeup. It's interesting to me how strongly the design of original radar displays anchors the project. Your toddler might never interact with a real CRT, much less an ASR-9 with a PPI display. But you've gone to great lengths to simulate one for her.
Partly because of your affinity for skeumorphism, as you said, but it may also be because the OG radar display is a fantastic distillation of "Is there something in the sky and where is it relative to me?" All the UIs we have for sky-watching now have moved away from that in favor of contextual data or linking out to other services (or creating space to display ads). In the process of presenting all that additional information, they've lost the ability to easily answer that particular question.
I like your comment — it points out that our RADAR displays were a both a product of the technology that was used to generate them (the sweep) but also that it was a deliberate way to make clear what it was you were observing (target distance was represented by distance from center, target bearing by angle around the circle).
To your point though, perhaps emulating the sweep was the questionable design decision — the bright colors, map-less background not controversial at all since they help focus on the intent of the display.
I did notice that as I turn with the phone, the compass-tracking feature broke the illusion of the sweep. :-)
This is a great point - it’d be easy to de-anchor the sweep from turning but it’d be enormously complex to re-write the logic for the planes to make them fade in their own time (using the angular gradient to accomplish both the sweep and the fade was probably the best shortcut of the whole project!)
Now I have a funny vision in my head of a WWII radio tech standing in a field, wearing an absurdly large RADAR rig, with a big sweeping antenna protruding from a backpack and a massive screen on his chest, turning this way and that, all confused by how the sweep doesn't look quite right...
That's not too far off, actually. Airborne radar as recently as the F-14 needed time to "settle down" an extrapolated track after maneuvering, to the point that they could give false indications of targets changing heading. This phantom turn looked aggressive and contributed to the US downing 2 Libyan fighter jets in 1989.
> Is there something in the sky and where is it relative to me?
One service that continues to capture this really well is the AR mode of FlightRadar24. I understand all of the individual bits of technology involved just fine (and run my own ADSB station!) but there's something about pointing a camera at the sky and seeing metadata of all the planes in view that still amazes me.
Partly because of your affinity for skeumorphism, as you said, but it may also be because the OG radar display is a fantastic distillation of "Is there something in the sky and where is it relative to me?" All the UIs we have for sky-watching now have moved away from that in favor of contextual data or linking out to other services (or creating space to display ads). In the process of presenting all that additional information, they've lost the ability to easily answer that particular question.