GraphConnect 2014 SF: Using a Graph Database to Ensure a Routable Road Network

1. MAP QA ANALYSIS WITH
Pieter Cailliau / @cailliaup

2. ABOUT ME
Graduated in Computer Science
Master thesis: Time based graph model for a dynamic route
planner
Started @TomTom in 2010
Unfortunately, I'm not related to Robert Cailliau

3. ABOUT

5. PRODUCTS OF

6. CONSUMER

7. AUTOMOTIVE

8. LICENSING

9. TELEMATICS

10. MAP EDITING PROCESS

13. EXAMPLE QA CHECKS

16. OUR MOST EXPENSIVE QA CHECKS

17. A Restricted Access Island (RAI) is a piece of the
Road Network where you can navigate locally
but not reach or leave globally.

19. THE RAI ALGORITHM

21. ROAD CATEGORIES

24. If you travel from A to B, a route exists that will
get you to your destination B in a strict
ascending order of road categories followed by a
strict descending order of road categories to B

25. THIS IS NOT A RAI!

26. THIS IS A RAI!

27. It is sufficient to know when changing a road X,
with RC(X)=i, that we can still reach* a road Y,
with RC(Y)>i, without going over a lower
RC.**/***
* reach means that we take all trafic restricitons into account.
** this transitivity works on condition that the highest road category is connected.
*** the inverse is also needed, from a higher RC towards road X.

28. BREADTH FIRST SEARCH

29. RAI CHECK FACTS

31. GRAPH DENSITY

33. RDBMS
Optimized for all our data
geospatial index
Average QA time = 40sec
Depth limitation of 100, 97% of violations found
New violations are added to our database

37. RDBMS + NEO4J
Optimized for routing/navigation
Average QA time = 5.2sec
No depth limitation
All RAI violations detected

38. NEO4J IMPLEMENTATION DETAILS
Embedded
High Availability
Semantic layer on top of it
Algorithms in java
Our graph model

39. LESSONS LEARNED

41. IT’S HARD TO MAINTAIN MULTIPLE “MATERIALIZED VIEWS”
OF OUR DATABASE

42. BRING YOUR CODE TO THE DATA

43. WHAT'S NEXT?
Migrate more QA Checks to Neo4J
Crawling agents

44. DEMO!

45. QUESTIONS?