LCSS - An implementation of LCSS Algorithm written in php-cpp

This is a simple implementation of the LCSS Algorithm, written in php-cpp, in order to get better performance compared with a pure PHP implementation.

Installation (Ubuntu or OS)

You can simply type make everything and the extension will be installed.

However if any errors occur, you can do the following :

1. Edit the Makefile and set INI_DIR to the directory that holds your additional .ini files.
2. make everything

Usage (PHP side)

LCSS( double epsilon [, double delta ] )

• The constant epsilon is the matching threshold (value between 0 and 1)

• The constant delta controls how far in time we can go in order to match a given point from one trajectory to a point in another trajectory.

double LCSS::findSimilarity( array trajectory1Lat, array trajectory1Lng, array trajectory2Lat, array trajectory2Lng )

• Currently Similarity Measures/ Similarity Function 1 is used.

Determining the values for epsilon and delta

The authors of the paper, suggest to find the minimal standard derivation between the two trajectories and use it as epsilon, while delta should be around 20%-30% of trajectories length.