When creating the ol.style.Style parameter of a ol.layer.Vector, is the stroke required for proper rendering of the MultiPolygon?
This is a modified version of the example code taken from here . When the stroke
parameter is commented out, the polygon renders as a 3 sided polygon. When uncommenting the stroke
parameter, the polygon renders correctly as a 4 sided polygon. This is a jsfiddle example. The code below assumes there is an html <div>
element with the id "map".
var styleFunction = (function() {
var styles = {};
styles['MultiPolygon'] = new ol.style.Style({
/*stroke: new ol.style.Stroke({
color: 'rgba(255, 255, 0, 1)',
width: 1
}),*/
fill: new ol.style.Fill({
color: 'rgba(255, 255, 0, 0.3)'
})
});
return function(feature) {
return styles[feature.getGeometry().getType()] || styles['default'];
};
})();
var geojsonObject = {
'type': 'FeatureCollection',
'crs': {
'type': 'name',
'properties': {
'name': 'EPSG:3857'
}
},
'features': [{
'type': 'Feature',
'geometry': {
'type': 'MultiPolygon',
'coordinates': [[[[841605, 6482619], [841599, 6482618], [841598, 6482623], [841600, 6482624]]]]
}
}]
};
var source = new ol.source.Vector({
features: (new ol.format.GeoJSON()).readFeatures(geojsonObject)
});
var layer = new ol.layer.Vector({
source: source,
style: styleFunction
});
var map = new ol.Map({
layers: [layer],
target: 'map',
view: new ol.View({
center: [841599.9364198849, 6482619.123901887],
zoom: 21
})
});
This is not a bug. The coordinates in the code snippet above are invalid. According to the GeoJSON specification , "The first and last positions are equivalent, and they MUST contain identical values;"
. For the above snippet, the correct coordinates array would be
'coordinates': [[[[841605, 6482619], [841599, 6482618], [841598, 6482623], [841600, 6482624], [841605, 6482619]]]]
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