Chapter 2 Trajectory Indexing and Retrival

This 26 pages paper is a bit short as a survey but a little too long for me the first day to write a “papaer analysis”. But I will finish it rather than give up in front of my first piece of work.

As a survey, I can learn some full-scale knowledge on the topic of Trajectory Indexing and Retrival.

If an paper has a smooth section setting, it’s convenient for readers to read and understand, this paper did.

Query Tricks:

1) Construct indecies;
2) when tranverse the index, Depth-first or width-first can be used. Then, the filter-and-refine paradigm is necessary.

1 Three Query

The central theme of the paper is three kinds of trajectory query:

1.1 P-Query

Two kinds:

• Given trajectories, ask for POI;
• Given POI(1 or more), ask for trajectories.

1.1.1 Ask for trajectories

1) Construct index: for line segment or sampled position
2) Filter-and-refine: remember to mark visited

1.1.2 Ask for POI

Fantastic Idea!

If there is a segment of (s, e), and a lot of POIs around it.
1) Search the POI nearest to s —- a;
2) Draw circles of (s,