How to get lat/lng coordinates from GEOMETRY('POINT') with Sequelize? - sql-server

Question

I have an MS SQL database that contains a table with latitude/longitude positions of some devices. These positions are stored in a GEOGRAPHY field. Now I want to get these positions from my node app with Sequelize.
Here's my sequelize model definition:
db.define('StationLocation', {
StationId: { type: Sequelize.INTEGER },
Position: { type: Sequelize.GEOMETRY('POINT') }
}
)
And here's what I currently get:
{
"id":4,
"StationId":1,
"Position":{
"type":"Buffer",
"data":[
230,
16,
0,
0,
1,
12,
25,
159,
112,
57,
112,
200,
73,
64,
0,
0,
0,
128,
184,
247,
26,
64
]
}
}
How can I convert this to latitude and longitude values? Is Sequelize able to do this?
Update: In the example above, the position is this:
Latitude: 51.565924816122966
Longitude: 6.741914749145508
Here's my query:
StationLocation
.findAll({ raw: true })
.then(function(allStationLocations) {
console.dir(allStationLocations[0].coordinates); // Just for debugging
res.send(JSON.stringify(allStationLocations));
});
This translates to this SQL statement:
SELECT [id], [StationId], [Position] FROM [StationLocations] AS [StationLocation];

Answer 1

Proper support for MSSQL geometry and geography data types is still pending. Tedious does however provide a parser for that buffer you get as a result: Tediousjs Geoparser
As a workaround for anyone having the same problem i've created an adapter utility, it's fairly simple to use but only supports points: Sequelize MSSQL Adapter
Require and use accordingly in your model definition, more info on the snippet's description.
const adapter = require('../utils/sequelize-geodata-adapter');
module.exports = (sequelize, DataType) =>
sequelize.define('MyModel', {
// Attributes
location: {
type: DataType.GEOGRAPHY('POINT', 4326),
get: function () {
const location = this.getDataValue('location');
if (location)
return adapter.get(location);
},
set: function (value) {
if (value === undefined || value === null)
return this.setDataValue('location', value);
this.setDataValue('location', adapter.set(value));
},
validate: {
hasCoordinates: adapter.validate
}
},
...
}, {
tableName: 'MyModels'
...
});
Setter supports GeoJSON and Google-style {lat, lng} location formats, getter always returns {lat, lng} objects.
In your particular case you'll need to replace geography::Point with geometry::Point at the adapter since you are using the GEOMETRY data type. Parser is indistinct for both.