1. Proprietary and
confidential
Aurore Jard
Mobile Lead Developer
“Design for tomorrow”
“Deconstruct what you know”
“Simplify”
“Love what you did”
@AuroreJard

2. April 12, 2016
Don’t lose your way optimizing
maps rendering !
Talk : map optimizations ! Confidential

3. Requirements
Confidential
● Display
○ Data as locality
○ Zone on map
● User feature
○ Move
○ Zoom
● Access offline
Talk : map optimizations !

4. SDK Fight
Confidential
● Map
○ https://developer.apple.com/maps/
● Google
○ https://developers.google.com/maps/documentation/ios-sdk/
Talk : map optimizations !
Google Map VS Apple Maps

5. SDK Fight
Confidential
● Official documentation
○ Maps
○ Google iOS SDK
● Application also available on android : same experience on both
● Map more precise
● More possibilities
Talk : map optimizations !

6. First : easy steps
Confidential
● Get Data
● Display data
Talk : map optimizations !

7. What about really a lot of data ?
ConfidentialTalk : map optimizations !

8. First impressions
Confidential
● UI/UX remarks
○ Users are humans !
■ Adapt data according to zoom level
■ Zone, details : only on high level of zoom
■ Regroup data that eye can dissociate
● Performances
○ Avoid treating data you don’t see...
Talk : map optimizations !

9. First : clustering
ConfidentialTalk : map optimizations !

10. First : clustering
Confidential
● Regroup close data
○ easier user reading
○ Indication on number of location
in one group
● Clustering possibilities :
○ Grid based clustering
○ Distance based clustering
Talk : map optimizations !

11. Easy optimizations :
Confidential
● Grid based clustering
Talk : map optimizations !

12. Easy optimizations :
Confidential
● Distance-based Clustering
Talk : map optimizations !

13. Second : don’t treat invisible data
Confidential
● Limitation :
○ Zoom level
Talk : map optimizations !

14. Third : More optimization on sorting data
Confidential
● Why does it take so long ?
● Iterate over each location : 0(n)
● Every move from the camera (move, zoom) need to iterate again
Talk : map optimizations !
for location in locations {
if visibleBounds.containsCoordinate(location.position) {
// item should be display
}
else {
// ignore this location
}

15. Third : More optimization on sorting data
Confidential
● Reduce complexity by using QuadTree object & algorithms !
● Objective : subdivision of 2D space
● QuadTree = Tree with 4 leafs
Talk : map optimizations !

16. Third : More optimization on sorting data
Confidential
● Step 1 :
○ Build the tree from your initial data
○ Keep iteration on all locations on that process
■ o(n) but only once
Talk : map optimizations !

17. Third : More optimization on sorting data
Confidential
● Step 2 :
○ Search for locations in a specific area
■ Everytime you move / zoom
Talk : map optimizations !

18. Third : More optimization on sorting data
Confidential
● Why is it faster ?
○ For loop only done once at initialisation
○ Search then (user interactions)
■ O(h) (h = max depth of node in the tree)
Talk : map optimizations !
h=0
h=1
h=2
h=3

19. Links / Resources
Confidential
● Code :
○ Open Source library for clustering with Google Map iOS SDK
○ Display Large Amount of Data on iOS Map
● MapKit Apple Sample
○ Apple Sample clustering
● Other
○ QuadTree Interactive Explanations
Talk : map optimizations !

20. Have fun with maps ;)
Thanks !
ConfidentialTalk : map optimizations !

21. Proprietary and
confidential
@NurunMTL
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