CMMotionActivityManager ignores cycling

问题:

I've been researching the new M7 chip's CMMotionActivityManager, for determining whether the user of the device is walking, running, in a car, etc (see Apple Documentation). This seemed like a great step forward over trying to determine this previous from using LocationManager and accelerometer data only.

I notice however that CMMotionActivityManager does not have a cycling activity, which is disappointing, and almost a deal-breaker for complete usage as a new activity manager. Has anyone else found a convenient way to use CMMotionActivityManager with cycling also without having to reincorporate CMLocationManager + accelerometer just to try to test for cycling too?

Note, this also does not include general transport options for things like a Train. For instance, I commute an hour a day on the train. Automotive could be made more generic at least, similar to how Moves uses Transport.

CMMotionActivity has these defined motion types only:

• stationary
• walking
• running
• automotive
• unknown

Useful notes from Apple's code, that does not necessarily solve the issue, but is helpful:

CMMotionActivity

An estimate of the user's activity based on the motion of the device.

The activity is exposed as a set of properties, the properties are not mutually exclusive.

For example, if you're in a car stopped at a stop sign the state might look like: stationary = YES, walking = NO, running = NO, automotive = YES

Or a moving vehicle, stationary = NO, walking = NO, running = NO, automotive = YES

Or the device could be in motion but not walking or in a vehicle. stationary = NO, walking = NO, running = NO, automotive = NO. Note in this case all of the properties are NO.

[Direct Source: Apple iOS Framework, CoreMotion/CMMotionActivity.h @interface CMMotionActivity, inline code comments]

回答1:

So, not sure if you still need an answer to that but here is the latest from iOs8 SDK

@property(readonly, nonatomic) BOOL cycling NS_AVAILABLE(NA, 8_0);

回答2:

First of all its your question or kind of informative details on M7?

Has anyone else found a convenient way to use CMMotionActivityManager with cycling also without having to reincorporate LocationManager + accelerometer just to try to test for cycling too?

See there is lots of confusion it will create if you want to check if activity is type of cycling ??because its just depend on accelerometer

accelerometer contain microscopic crystal structures that get stressed by accelerative forces, which causes a voltage to be generated.and from that voltage it can parse the result.. so what i know is its just classifies your speed and giving you result that its running walking or automotive so if you want to use cycling some time very fast very slow or medium so may be it will some time result in to walking or running or may be auotomotive so m7 can not clarify the thing if its automotive or cycling or running because there is not much of speed variance while you cycling.

Still while using for running and walking its some time gives wrong results in some cases.. so that will chances that your app will give wrong information too.

One more thing you asked is

Note, this also does not include general transport options for things like a Train. For instance, I commute an hour a day on the train. Automotive could be made more generic at least, similar to how Moves uses Transport.

So Apple is also working on other mapping features. Apple is said to be planning notable updates to its Maps app in iOS 8, and the company is currently working on implementing both public transit directions and indoor mapping features (which Google already has on iOS).

http://www.macrumors.com/2013/09/12/apple-working-to-leverage-new-m7-motion-sensing-chip-for-mapping-improvements/ (Useful Link)

回答3:

In session 612 at WWDC 2014, the two presenting Apple engineers provided some information: In the slides they stated:

Performance is very sensitive to location

• Works best if device is worn on upper arm Best for retrospective use cases

Longest latency

• Best for retrospective use cases

In the video they explain on the audio track (starting at about 11:00) that

Cycling is new, something we introduced in iOS 8. Cycling is very challenging, and again you need the dynamics and so it's going to be very sensitive to location. If it was mounted on the upper arm the latency is going to be fairly reasonable. And if it's anywhere else, it's going to take a lot longer. So definitely I would not suggest using cycling activity classification as a hint for the context here and now. It's really something that you'll want to use in a retrospective manner for a journaling app, for example.

I made a simple test setup for iOS 8 and 9 and iPhone 5s and 6 and cycling was not detected - not a single time in over 1.5h cycling. If the new iPhone 6S makes good this major deficit in motion activity detection is unclear - Phil Schiller announced it in September 2015.

tl;tr

Currently, cycling detection in CoreMotion does not work as it works for stationary, walking, running, and car! It will be not detected and can be used retrospectively only.