               var coordinates = feature.coordinates;
                    var [from, to] = coordinates;
                    var lnglats = [[parseFloat(from[0]), parseFloat(from[1])], [parseFloat(to[0]), parseFloat(to[1])]]
                    return new maptalks.LineString(lnglats);
                });

                var timer = 'generate line time';
                console.time(timer);
                var list = [];
                lineStrings.forEach(lineString => {
                    list.push({
     