mapVisual.js

return function (ecModel) {
    ecModel.eachSeriesByType('map', function (seriesModel) {
        var colorList = seriesModel.get('color');
        var itemStyleModel = seriesModel.getModel('itemStyle.normal');

        var areaColor = itemStyleModel.get('areaColor');
        var color = itemStyleModel.get('color')
            || colorList[seriesModel.seriesIndex % colorList.length];

        seriesModel.getData().setVisual({
            'areaColor': areaColor,
            'color': color
        });
    });
};