ais_expand_skiplist.c File Reference

A simple program that reads AIS data from a CSV file containing one full day of observations provided by the Danish Maritime Authority in https://web.ais.dk/aisdata/, constructs for each ship temporal values for the trip and the SOG, and outputs for each ship the MMSI, the number of records and instants used for contruct the temporal values, the distance travelled and the time-weighted average of the SOG. More...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <meos.h>
#include <meos_geo.h>
#include <meos_internal.h>
#include <meos_internal_geo.h>

Data Structures
struct	AIS_record
struct	trip_record

Macros
#define	INITIAL_INSTANTS   64
#define	MAX_LENGTH_LINE   1024
#define	MAX_LENGTH_POINT   64
#define	MAX_LENGTH_STRING   64
#define	MAX_LENGTH_TIMESTAMP   32
#define	MAX_NO_RECORDS   20000000
#define	NO_RECORDS_BATCH   100000

Functions
int	main (void)
void	rec_skiplist_free (SkipList *list)
	Specific free function for the skiplist that also frees the temporal values in the record values. More...
int	trip_comp_fn (void *left, void *right)
void *	trip_merge_fn (void *left, void *right)

Detailed Description

A simple program that reads AIS data from a CSV file containing one full day of observations provided by the Danish Maritime Authority in https://web.ais.dk/aisdata/, constructs for each ship temporal values for the trip and the SOG, and outputs for each ship the MMSI, the number of records and instants used for contruct the temporal values, the distance travelled and the time-weighted average of the SOG.

Please notice that the data directory DOES NOT contain the input CSV file, you must download it from the website above.

Please read the assumptions made about the input CSV file in the file 02_ais_read.c in the same directory. The program uses a compilation constraint that can be used to reduce the number of records in processed. Also, the program copes with minimal error correction, that is,

• It supposes that the observations have increasing timestamp values
• It verifies that the latitude, longitude, and SOG values read are in specified ranges, and
• It takes only the first observation when there are two or more observations for the same ship with equal timestamp values.

The program can be build as follows

gcc -Wall -g -I/usr/local/include -o ais_expand_skiplist ais_expand_skiplist.c -L/usr/local/lib -lmeos