I am implementing Mapkit in iOS application to make an application which shows posts to users based on his/her location like tinder do. I have tried an algorithm which calculates distance based on coordinates between user and posts. But it seems to be a very costly solution in terms of time, it has a very high complexity, i just wanted to ask is it the right way am doing or should i change my approach. Thank You.
You can you Google API to find the distance between a origin & destination and update the posts aysnc. Hope it helps
Note: You can also pass multiple origins in a single request.
This is a general question seeking advice on the pattern required to calculate a user's velocity / pace / speed, when running or swimming.
Specifically, I want to be able to calculate this from watch OS, disconnected from the companion phone.
With GPS capabilities of Watch 3 / Watch OS 10.0 would the best approach be to:
Start Location Manager
Calculate distance and time between location points...
Calculate average speed?
Or are there better alternatives?
There is a good article here https://www.bignerdranch.com/blog/watchkit-2-hardware-bits-the-accelerometer/ that recommends using CoreMotion for device speed. However, this in my view would rather represent the 'device-speed' and not necessarily the user's speed over distance.
Any advice or experiences would be much appreciated.
Thanks.
The article you linked to is for WatchOS 2, not Watch 2. The motion tracking is pretty good, but to get accurate device speed you will still need to use the GPS.
If you don't need to do any other location related calculations, and don't need real time data (EDIT you can get near real time data with an HKAnchoredObjectQuery. This is sufficient for most situations) then you don't need to start location manager, just an HKWorkoutSession. This will default to using the GPS or Motion Data (which ever is more accurate/available at the time) and manage everything for you. When the workout is over, you can query for the distance samples and calculate pace from that.
If you need live motion data then the steps you outlined are correct, however you should check that the user is outdoors first. If the user is indoors or has a weak GPS signal switch to using Motion Data (and be sure to set the HKMetadataKeyIndoorWorkout appropriately if using HealthKit).
I would like to develop a mobile app for iPhones, that calculates time needed to reach a given velocity. For example: I'm in my car, open the app, choose 100km/h and when I accelerate the app should start to count time and it stops counting just in the moment when I reach 100km/h. It should be very accurate.
I heard about two solutions. First is to use the accelerometer/gyroscope, but some people told me it's bad idea, because I won't be able to calculate time on longer distances. The second option is to use GPS, but on the other hand it can be not as accurate as I want it to be.
So I need suggestions, which option is better and why.
My targets are iPhones 4s and newer.
If you want to be more precise than the GPS you will need to have some sort of sensor. Most similar apps and concepts will create a receiver that plugs into the car that the iPhone can connect to. This has the benefit of making all of the sensors in the car available to you. This is an example: https://www.automatic.com/how-automatic-works/
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]
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)
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);
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.
I'm looking to use the CMMotionActivity for iPhone 5s's, but also want to be able to use similar functionality on older iPhone's, is this possible?
Could I create a less accurate alternative maybe, by tracking GPS and not using the M7 chip? Any advice/tutorials/sample code?
You can create your own algorithm which will utilize accelerometer data and estimate number of steps taken. Its not as accurate and its not a good idea to have 2 separate logic in the same app.
In case, you want to give it a try, check this answer..How to count steps using an Accelerometer?