GraphConnect 2014 SF: Using a Graph Database to Ensure a Routable Road Network
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Transcript of GraphConnect 2014 SF: Using a Graph Database to Ensure a Routable Road Network
MAP QA ANALYSIS WITH
/ Pieter Cailliau @cailliaup
ABOUT MEGraduated in Computer Science
Master thesis: Time based graph model for a dynamic routeplanner
Started @TomTom in 2010
Unfortunately, I'm to not related Robert Cailliau
ABOUT
PRODUCTS OF
CONSUMER
AUTOMOTIVE
LICENSING
TELEMATICS
MAP EDITING PROCESS
EXAMPLE QA CHECKS
OUR MOST EXPENSIVE QA CHECKS
A Restricted Access Island (RAI) is a piece of theRoad Network where you can navigate locally
but not reach or leave globally.
THE RAI ALGORITHM
ROAD CATEGORIES
If you travel from A to B, a route exists that willget you to your destination B in a strict
ascending order of road categories followed by astrict descending order of road categories to B
THIS IS NOT A RAI!
THIS IS A RAI!
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 lowerRC.**/***
* 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.
BREADTH FIRST SEARCH
RAI CHECK FACTS
GRAPH DENSITY
RDBMSOptimized 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
RDBMS + NEO4JOptimized for routing/navigation
Average QA time = 5.2sec
No depth limitation
All RAI violations detected
NEO4J IMPLEMENTATION DETAILSEmbedded
High Availability
Semantic layer on top of it
Algorithms in java
Our graph model
LESSONS LEARNED
IT’S HARD TO MAINTAIN MULTIPLE “MATERIALIZED VIEWS”OF OUR DATABASE
BRING YOUR CODE TO THE DATA
WHAT'S NEXT?Migrate more QA Checks to Neo4J
Crawling agents
DEMO!
QUESTIONS?