GoMEOS

MEOS (Mobility Engine, Open Source) is a C library which enables the manipulation of temporal and spatio-temporal data based on MobilityDB's data types and functions.

GoMEOS is a Go library that wraps the MEOS C library using CGO, providing a set of Go functions that allows to use MEOS functionality by directly accessing C structs and C functions.

GoMEOS exposes the functionality of MEOS and is meant to be used directly by the user.

Usage

Installation

You'll need to install the MEOS library by compling MobilityDB.

git clone git@github.com:MobilityDB/MobilityDB.git
cd MobilityDB
mkdir build
cd build
cmake -DMEOS=on ..
make
sudo make install

GoMEOS requires CGO (CGO_ENABLED=1) in order to be built.

Then install GoMEOS by go get command.

go get github.com/MobilityDB/GoMEOS

Quick Start

IMPORTANT Before using any GoMEOS function, always call MeosInitialize(). Otherwise, the library will crash with a Segmentation Fault error. You should also always call MeosFinalize() at the end of your code.

// main.go
package main

import (
	"fmt"

	gomeos "github.com/MobilityDB/GoMEOS"
)

func main() {
	gomeos.MeosInitialize("UTC")

	/* Input temporal points in WKT format */
	inst_wkt := "POINT(1 1)@2000-01-01"
	seq_disc_wkt := "{POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02}"
	seq_linear_wkt := "[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02]"
	seq_step_wkt := "Interp=Step;[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02]"
	ss_linear_wkt := "{[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02],[POINT(3 3)@2000-01-03, POINT(3 3)@2000-01-04]}"
	ss_step_wkt := "Interp=Step;{[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02],[POINT(3 3)@2000-01-03, POINT(3 3)@2000-01-04]}"

	/* Read WKT into temporal point object */
	inst := gomeos.NewTGeomPointInst(inst_wkt)
	seq_disc := gomeos.NewTGeomPointSeq(seq_disc_wkt)
	seq_linear := gomeos.NewTGeomPointSeq(seq_linear_wkt)
	seq_step := gomeos.NewTGeomPointSeq(seq_step_wkt)
	ss_linear := gomeos.NewTGeomPointSeqSet(ss_linear_wkt)
	ss_step := gomeos.NewTGeomPointSeqSet(ss_step_wkt)

	fmt.Println("--------------------Temporal Instant--------------------")
	fmt.Println(inst.TPointOut(5))
	fmt.Println("--------------------Temporal Sequence with Discrete Interpolation--------------------")
	fmt.Println(seq_disc.TPointOut(5))
	fmt.Println("--------------------Temporal Sequence with Linear Interpolation--------------------")
	fmt.Println(seq_linear.TPointOut(5))
	fmt.Println("--------------------Temporal Sequence with Step Interpolation--------------------")
	fmt.Println(seq_step.TPointOut(5))
	fmt.Println("--------------------Temporal Sequence Set with Linear Interpolation--------------------")
	fmt.Println(ss_linear.TPointOut(5))
	fmt.Println("--------------------Temporal Sequence Set with Step Interpolation--------------------")
	fmt.Println(ss_step.TPointOut(5))
	gomeos.MeosFinalize()
}

To run this file:

go build main.go
./main

output:
--------------------Temporal Instant--------------------
POINT(1 1)@2000-01-01 00:00:00+00
--------------------Temporal Sequence with Discrete Interpolation--------------------
{POINT(1 1)@2000-01-01 00:00:00+00, POINT(2 2)@2000-01-02 00:00:00+00}
--------------------Temporal Sequence with Linear Interpolation--------------------
[POINT(1 1)@2000-01-01 00:00:00+00, POINT(2 2)@2000-01-02 00:00:00+00]
--------------------Temporal Sequence with Step Interpolation--------------------
Interp=Step;[POINT(1 1)@2000-01-01 00:00:00+00, POINT(2 2)@2000-01-02 00:00:00+00]
--------------------Temporal Sequence Set with Linear Interpolation--------------------
{[POINT(1 1)@2000-01-01 00:00:00+00, POINT(2 2)@2000-01-02 00:00:00+00], [POINT(3 3)@2000-01-03 00:00:00+00, POINT(3 3)@2000-01-04 00:00:00+00]}
--------------------Temporal Sequence Set with Step Interpolation--------------------
Interp=Step;{[POINT(1 1)@2000-01-01 00:00:00+00, POINT(2 2)@2000-01-02 00:00:00+00], [POINT(3 3)@2000-01-03 00:00:00+00, POINT(3 3)@2000-01-04 00:00:00+00]}

For more examples, you can see the examples.

// Run ais.go example
git clone git@github.com:MobilityDB/GoMEOS.git
cd GoMEOS
go run examples/ais/assemble/ais.go

Documentation

Visit pkg.go.dev for a more complete and detailed documentation.