My First MEOS Program
This program creates some temporal values from their WKT format and output them in MF-JSON format.
The output of the program is given next.
--------------------
| Temporal Instant |
--------------------
WKT:
----
POINT(1 1)@2000-01-01
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
1,
1
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-01T00:00:00+01"
}
},
"coordinates": [
1,
1
],
"datetimes": "2000-01-01T00:00:00+01",
"interpolations": [
"Discrete"
]
}
-------------------------------------------------
| Temporal Sequence with Discrete Interpolation |
-------------------------------------------------
WKT:
----
{POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02}
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
2,
2
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-02T00:00:00+01"
}
},
"coordinates": [
[
1,
1
],
[
2,
2
]
],
"datetimes": [
"2000-01-01T00:00:00+01",
"2000-01-02T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true,
"interpolations": [
"Discrete"
]
}
-----------------------------------------------
| Temporal Sequence with Linear Interpolation |
-----------------------------------------------
WKT:
----
[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02]
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
2,
2
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-02T00:00:00+01"
}
},
"coordinates": [
[
1,
1
],
[
2,
2
]
],
"datetimes": [
"2000-01-01T00:00:00+01",
"2000-01-02T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true,
"interpolations": [
"Linear"
]
}
-------------------------------------------------
| Temporal Sequence with Stepwise Interpolation |
-------------------------------------------------
WKT:
----
Interp=Stepwise;[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02]
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
2,
2
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-02T00:00:00+01"
}
},
"coordinates": [
[
1,
1
],
[
2,
2
]
],
"datetimes": [
"2000-01-01T00:00:00+01",
"2000-01-02T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true,
"interpolations": [
"Stepwise"
]
}
---------------------------------------------------
| Temporal Sequence Set with Linear Interpolation |
---------------------------------------------------
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]}
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
3,
3
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-04T00:00:00+01"
}
},
"sequences": [
{
"coordinates": [
[
1,
1
],
[
2,
2
]
],
"datetimes": [
"2000-01-01T00:00:00+01",
"2000-01-02T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true
},
{
"coordinates": [
[
3,
3
],
[
3,
3
]
],
"datetimes": [
"2000-01-03T00:00:00+01",
"2000-01-04T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true
}
],
"interpolations": [
"Linear"
]
}
-----------------------------------------------------
| Temporal Sequence Set with Stepwise Interpolation |
-----------------------------------------------------
WKT:
----
Interp=Stepwise;{[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02],[POINT(3 3)@2000-01-03, POINT(3 3)@2000-01-04]}
MF-JSON:
--------
{
"type": "MovingGeomPoint",
"stBoundedBy": {
"bbox": [
[
1,
1
],
[
3,
3
]
],
"period": {
"begin": "2000-01-01T00:00:00+01",
"end": "2000-01-04T00:00:00+01"
}
},
"sequences": [
{
"coordinates": [
[
1,
1
],
[
2,
2
]
],
"datetimes": [
"2000-01-01T00:00:00+01",
"2000-01-02T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true
},
{
"coordinates": [
[
3,
3
],
[
3,
3
]
],
"datetimes": [
"2000-01-03T00:00:00+01",
"2000-01-04T00:00:00+01"
],
"lower_inc": true,
"upper_inc": true
}
],
"interpolations": [
"Stepwise"
]
}
The above ouput uses the pretty-printing options provided by the json-c library to facilite human reading. By changing the corresponding flag in the program it is possible to obtain a more compact machine-processable representation.
A similar result can be obtained in MobilityDB with the following SQL query.
WITH temp(k, t) AS (
SELECT 1, tgeompoint 'POINT(1 1)@2000-01-01' UNION
SELECT 2, tgeompoint '{POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02}' UNION
SELECT 3, tgeompoint '[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02]' UNION
SELECT 4, tgeompoint '{[POINT(1 1)@2000-01-01, POINT(2 2)@2000-01-02], [POINT(3 3)@2000-01-03, POINT(3 3)@2000-01-04]}'
)
SELECT asEWKT(t), asMFJSON(t,1) FROM temp
ORDER BY k;