一、图层样式配置规则

1. 规则配置使用到 OpenLayers 中的比较过滤器 OpenLayers.Filter.Comparison
2. 常见的属性有

• type：比较的类型
• property：要比较的上下文属性的名称
• value：用于二进制比较的{Number}或{String}比较值

let getstyle = () => {
    var style = new OpenLayers.Style(
        {
            pointRadius: 6,
            fillOpacity: 1,
            strokeWidth: 1,
            strokeOpacity: 1,
            graphicZIndex: 1
        },
        {
            rules: [
                new OpenLayers.Rule({
                    filter: new OpenLayers.Filter.Comparison({
                        type: OpenLayers.Filter.Comparison.EQUAL_TO,
                        property: "color_flag",
                        value: 1
                    }),
                    symbolizer: {
                        fillOpacity: 1,
                        fillColor: "#FFFF00",
                        strokeWidth:1,
                        strokeOpacity: 1,
                        strokeColor: "#FFFF00"
                    }
                }),
                new OpenLayers.Rule({
                    filter: new OpenLayers.Filter.Comparison({
                        type: OpenLayers.Filter.Comparison.EQUAL_TO,
                        property: "color_flag",
                        value: 2
                    }),
                    symbolizer: {
                        fillOpacity: 1,
                        fillColor: "#CDCD00",
                        strokeWidth:1,
                        strokeOpacity: 1,
                        strokeColor: "#CDCD00"
                    }
                }),
                new OpenLayers.Rule({
                    filter: new OpenLayers.Filter.Comparison({
                        type: OpenLayers.Filter.Comparison.EQUAL_TO,
                        property: "color_flag",
                        value: 3
                    }),
                    symbolizer: {
                        fillOpacity: 1,
                        fillColor: "#ED1C24",
                        strokeWidth:1,
                        strokeOpacity: 1,
                        strokeColor: "#ED1C24"
                    }
                }),
                new OpenLayers.Rule({
                    filter: new OpenLayers.Filter.Comparison({
                        type: OpenLayers.Filter.Comparison.EQUAL_TO,
                        property: "color_flag",
                        value: 4
                    }),
                    symbolizer: {
                        fillOpacity: 1,
                        fillColor: "#CD3232",
                        strokeWidth:1,
                        strokeOpacity: 1,
                        strokeColor: "#CD3232"
                    }
                }),
                new OpenLayers.Rule({
                    elseFilter: true,
                    symbolizer: {
                        fillOpacity: 1,
                        fillColor: "#FFFF00",
                        strokeWidth:1,
                        strokeOpacity: 1,
                        strokeColor: "#FFFF00"
                    }
                })
            ]
        }
    );
    return style
};

二、使用

// 1.创建一个图层,样式使用的就是上面定义的样式
let layers = new OpenLayers.Layer.Vector(
"基础图层",
{
    styleMap:new OpenLayers.StyleMap({
        "default": getstyle()
    })
});

map.addLayer(layers);

// 2.面信息
let polygon = "POLYGON((12620066.678926 2647759.0245114,12620066.678926 2647729.0245114,12620096.678926 2647729.0245114,12620096.678926 2647759.0245114,12620066.678926 2647759.0245114))";

// 3.读取feature
let feature =  new OpenLayers.Format.WKT().read(polygon);

// 4.扩展一个属性color_flag
$.extend(feature.attributes, { color_flag : 1 });

// 4.添加feature到图层上
map.getLayersByName('基础图层')[0].addFeatures(feature);

三、扩展

1. type：比较的类型

• OpenLayers.Filter.Comparison.EQUAL_TO =“ ==”;
• OpenLayers.Filter.Comparison.NOT_EQUAL_TO =“！=”;
• OpenLayers.Filter.Comparison.LESS_THAN =“ <”;
• OpenLayers.Filter.Comparison.GREATER_THAN =“>”;
• OpenLayers.Filter.Comparison.LESS_THAN_OR_EQUAL_TO =“ <=”;
• OpenLayers.Filter.Comparison.GREATER_THAN_OR_EQUAL_TO =“> =”;
• OpenLayers.Filter.Comparison.BETWEEN =“ ..”;
• OpenLayers.Filter.Comparison.LIKE =“〜”;
• OpenLayers.Filter.Comparison.IS_NULL =“ NULL”;

2. OpenLayers.Format.WKT

• read(polygon) =>返回一个Feature对象
• write(feature) =>返回一个字符串的面的信息