保存交互繪製開放層

Question

任何人都可以給我一個提示，我如何保存我在openlayers 3中繪製的交互繪圖？我可以使用json嗎？任何人都可以提供一個簡單的例子？

謝謝！

Answer 1

var features = yourLayer.getSource().getFeatures(); 
var newForm = new ol.format.GeoJSON(); 
var featColl = newForm.writeFeaturesObject(features); 

然後將其保存到JSON：

function exportJson(featuresCollection) { 
    var txtArray = []; 
    txtArray.push(JSON.stringify(featuresCollection)); 

// Here I use the saveAs library to export the JSON as *.txt file 

    var blob = new Blob(txtArray, {type: 'text/json;charset=utf8'}); 
    saveAs(blob, layerName + ".txt") 
}; 

exportJson(featColl); 

要加載JSON：

var vectorLayer = new ol.layer.Vector({ 
    source: new ol.source.GeoJSON({ 
    projection: 'EPSG:3857', 
    url: 'yourFile.json' 
    }) 
});