CODEWITHSUNDEEP
jqueryjsonpgeojsonopenlayers-3
Single Entity
Single Entity

Reputation: 3115

How to convert geoJSON format from jsonp request to Open Layers 3 friendly format

I am using a jsonp request to a server which is returning a string containing the geometry of a multiline vector. This looks like this (I've truncated it a little):

MULTILINESTRING((-0.61122 44.88987,-0.61108 44.88961,-0.6109 44.88926))

In Open Layers 3, when I usually create a vector feature I provide a string containing the geometry using the following code:

var vectorFeature = new ol.Feature({
    geometry: new ol.geom.MultiLineString([[-0.11151,21.24112],[-0.11151,81.24112]])
});

Notice the difference in the formatting of the strings. Is there a way in Open Layers 3 of quickly reformatting the response from the jsonp request to allow me to quickly create a new vector feature based on this data, or am I going to have to parse the string and add the [] formatting myself?

Edit:

If I use the object returned from the JSONP request as an argument in MultiLineString directly (as follows):

var vectorFeature = new ol.Feature({
geometry: new ol.geom.MultiLineString(data.geometry)
});

then if I attempt to retrieve the co-ordinates of the object using:

console.log(vectorFeature.getGeometry().getCoordinates());

I get Array[ Array[1], Array[1], Array[1]... ]

Which isn't correct, and to me points towards the incorrect formatting of the supposedly geoJSON object?

Edit 2

The object being returned from the JSON request turned out to be WKT and not geoJSON which explains the difficulties.

Upvotes: 0

Views: 694

Answers (2)

mcepl
mcepl

Reputation: 2786

The reply looks like WKT to me, isn’t it? OpenLayers have support for it directly.

Upvotes: 0

iH8
iH8

Reputation: 28638

In my opinion, using a regex would be a good solution in this case:

var string = 'MULTILINESTRING((-0.61122 44.88987,-0.61108 44.88961,-0.6109 44.88926))',
    matches = string.match(/(\-?\d+(\.\d+)?)\s(\-?\d+(\.\d+)?)+/g),
    results = [];

matches.forEach(function (match) {
    results.push(match.split(' '));
});

Returns results as a nested array object:

[
    ["-0.61122","44.88987"],
    ["-0.61108","44.88961"],
    ["-0.6109","44.88926"]
]

Working example on Plunker: http://plnkr.co/edit/mEjuaoPqWM0Zy6Y0RHER?p=preview

A sidenote, the string you get returned from the server isn't GeoJSON:

MULTILINESTRING((-0.61122 44.88987,-0.61108 44.88961,-0.6109 44.88926))

A proper GeoJSON MultiLineString geometry would look like this: 

{
    "type": "MultiLineString",
    "coordinates": [
        [[100.0, 0.0], [101.0, 1.0]],
        [[102.0, 2.0], [103.0, 3.0]]
    ]
}

Reference specification: http://geojson.org/geojson-spec.html#id6

Upvotes: 1

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