I get 227. Remember, you need to input the diagonal length of the screen. For the 38mm version, it is 1.915" [38mm^2+30.4mm^2)^0.5]/25.4 = 1.915
Granted, this is low-end because I didn't factor in the bezel, but I think somewhere around 250-270 is plausible.
The bezel makes a big difference in the PPI
Bigger one 390*312 = 121680 pixels
Smaller one. 340*272 = 92480
(a 2.5 mm bezel gives, counting rounding)
Bigger one : 1.7 square inch (37*29.6 = 1767) / (25.4*25.4) , so we have 121680 / 1.7 = (268 ppi) squared
Smaller one: 1.34 square inch (33mm x 26.2mm = 864.6 ) / (25.4*25.4) , So we have 92480 / 1.34 = (263 ppi)squared
So, around 265 ppi
(With a 4mm bezel, counting rounding)
Bigger one : 1.43 (34 * 27.2) / (25.4*25.4) , so we have 121680 / 1.27 = (291 ppi) squared
Smaller one : 1.116 (30 * 24 ) / (25.4 * 25.4) , so we have 92480/1.27= (288ppi) squared
So, 265-290 ppi
My feeling is the bezel is more than 2.5 mm on both side, so my gut is saying that the watch has :
280 PPI for both sizes.
----------
Overall first impressions:
1) They are taking a "second screen" strategy to the Apple Watch. There is no concept of a stand alone watch app. This is a big break for both Pebble and Google Wear.
2) The Xcode interface was a bit clunky. Took a bit to figure out how to show the watch screen in the simulator.
3) There should be a feature to simulate an Apple Watch on an iOS device that is provisioned for development. Thus, you have your iOS app run on one iOS device and another iOS device showing the Apple Watch views. An iPod Touch is excellent for this.
4) Apple Watch "apps" are just an extension of an iPhone app. Thus, to use Apple Watch "apps" you need an iPhone. No third party connectivity to Android nor Windows smart phones.
5) There is a proprietary wireless link (probably BLE without the throttling) between iPhone and Apple Watch to get apps on the watch using the WatchKit extensions.
6) The narrative voice in the half hour tutorial was really annoying. It is probably a product manager that won or lost the office draw. If they can afford to keep a staffed sound studio in the loop, they can afford a good voice actor.
7) This avoids a new product type in the App Store. It is just an "Apple Watch Enabled" category in the store.
8) It was probably targeted for this Christmas season but due to the Sapphire Crystal Greek Tragedy, it is delayed 'til 1Q15.
9) Dozens of millionaires to be made from the new generation of "fart apps." If you are coding now, don't look for the best, just look the fun and stupid.
10) If someone can spend $4000 for a gold Edition Apple Watch, you can charge $100 for a high end app. Go for it.
11) While there is money in making apps. There is a HUGE market for custom, third party Apple Watch wristbands.
I think will do as always. Be very tight about what goes on the watch, and how people are using watch resources, at first, then they will open it up once they're sure all is going fine on the watch. That way people don't blame Apple if apps mess up their watch.