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This is a must attend session for developers either planning to use or already using Android GPS in your native applications. Android offers one of the most flexible GPS systems that are available in smartphones today. We'll look at key aspects of the Location Manager Class, and provide real-world use cases on how to best implement them. You'll walk away with insight that typically takes days or even weeks to figure out.
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Android GPS Deep Dive! Na2ve and Browser
Andy Gup, Esri www.andygup.net
@agup
I
GPS
Who am I? Andy Gup Web, Mobile Developer Evangelist www.andygup.net github.com/andygup [email protected] @agup
Is smartphone GPS right for you?
Understanding use cases Understanding smartphone GPS! Deciding accuracy thresholds
Two open source tes2ng tools
Android GPS Test Tool
HTML5 Geoloca2on Test Tool
Six types of loca2on data
Real-‐2me GPS Network
Cached GPS Network
Passive NMEA
Two types of loca2on data
Real-‐2me Cached
Android SDK Java based Loca2onManager Loca2on APIs
Significantly more control over data providers baVery life offline usage when app is minimized
HTML5 Geoloca2on API
JavaScript-‐based Significantly less control over which providers are used baVery life
Can’t be used when minimized
Horizontal and ver2cal Grades:
Recrea2onal Map Survey High-‐end Survey
Accuracy Requirements
Horizontal and ver2cal Grades:
Recrea2onal > 3 m/10 `* (Android, iOS, iPad, Garmin, etc) Map 1 – 3 meters/3.2 – 9.8 `* Survey < 1 m/3.2 `* High-‐end Survey < 50 cm/1.6 `*
Accuracy Requirements
* Approxima2ons
Horizontal and ver2cal Grades:
Recrea2onal -‐ $ (Android, iOS, iPad, Garmin, etc) Map -‐ $$ Survey -‐ $$$ High-‐end Survey -‐ $$$$
Costs
Accuracy fluctuates…moves around…!!
Recrea2onal-‐grade accuracy??
Horizontal and ver2cal
< 1 cm = boundary/survey marker, gas line < 1 m = manhole cover, 1 – 3 meters = tree, trail head, junc2on box, pothole 3 – 10 meters = roo`op, fire hydrant 10 – 100 meters = parking lot, pond 100 – 1000 meters = park, neighborhood > 1000 meters = zip code area, drainage area
Recrea2onal-‐grade accuracy??
Example of accuracy 2ers:
3 – 10 meters = GOOD 10 – 100 meters = MAYBE 100 – 1000 meters = REJECT > 1000 meters = REJECT
Recrea2onal-‐grade accuracy??
10 – 100 meters 100 – 1000 meters > 1000 meters
Smartphone Accuracy
Accuracy
Depends on many things: Device type Which loca2on providers enabled Wifi turned on/off Cellular provider Country
Accuracy
GPS Test by ChartCross
Accuracy
Depends on many things: Rural (open sky) Near a building Inside a car Downtown Indoors
Higher accuracy
Lower accuracy
Denver Pepsi Center
~33 feet/10 meters (radius) 3422 sq </314.28 sq. m
Image courtesy Google Streetview
~99 feet/30 meters
328 feet/100 meters
~3280 feet/1000 meters
GPS: Cold vs. Warm
versus
Cold start
Phone rebooted Updated phone OS Poten2al for no cached values Poten2al for large inaccuracy Has to ‘acquire’ the satellites
Cold start
Cold Start: Snapshot
One-‐2me loca2on >= minimum accuracy Example: Standing indoors ~2 mins Accuracy 20 meters
Cold Start: Snapshot
One-‐2me loca2on >= minimum accuracy Example: Standing indoors ~3 mins Accuracy 3 meters
Cold Start: No GPS or Wifi
Warm start
Cached loca2ons available GPS has been run recently
Example: ~4 seconds Accuracy 11 meters
Warm start
Warm Start: GPS + Wifi (downtown)
Warm: Accuracy can s2ll fluctuate
Warm: Accuracy can s2ll fluctuate
Warm or cold…who cares??
BaVery life User expecta2ons Leave GPS on? Cycle GPS intermiVently?
BaVery life
How to get beVer baVery life??
External baVery solu2on examples: Anker Astro Series (up to 20,000 mAh) Energizer XP Series (up to 18,000 mAh) Mophie Juice (up to 6,000 mAh)
How to get beVer baVery life??
How to get beVer accuracy??
External GPS receiver (Wifi, bluetooth, plug-‐in) Consumer examples: Garmin GLOTM
Bad Elf GPS XGPS150A
How to get beVer accuracy??
How to get beVer accuracy??
HTML5 Geoloca2on Overview
Limited control over GPS and baVery Cannot be minimized Can approximate loca2on w/o GPS Gets loca2on faster when used w/ Wifi Requires JavaScript development experience
Na2ve GPS Overview
Fine grained control over GPS and baVery Works when minimized Requires Java development experience
Collector for ArcGIS
hVp://resources.arcgis.com/en/collector/
References www.gps.gov hVp://www.andygup.net/android-‐gps/ Mastering HTML5 Geoloca2on: hVps://www.dropbox.com/s/p6940ejtncoedyq/HTML5Geoloca2on%202.pptx Mastering Android GPS: hVps://www.dropbox.com/s/0fak3oziqyaj7i6/OSCON_MasterAndroidGeoloca2on.pptx Android GPS Test tool: hVps://github.com/Esri/android-‐gps-‐test-‐tool HTML5 Geoloca2on Test tool: hVps://github.com/Esri/html5-‐geoloca2on-‐tool-‐js
References Recrea2onal vs. Professional GPS: hVp://www.esri.com/news/arcuser/0104/rec-‐gps.html Smartphones, Tables and GPS Accuracy: hVp://blogs.esri.com/esri/arcgis/2013/07/15/smartphones-‐tablets-‐and-‐gps-‐accuracy/
Ques2ons? Andy Gup Developer Evangelist www.andygup.net github.com/andygup [email protected] @agup
