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[英]How to filter multiple layers by same attribute in ArcGis with JavaScript
[英]How to apply filter for multiple layers when using object in JavaScript for ArcGis
我正在使用 ArcGis JavaScript API 来显示一些地图。 我在对象中有特征层的 ID,如下所示:
const layersByYears = [
{ year: 1918, layers: [
{ layerID: "443709212b894e9297888b3194b51100", opacity: 1.0, name: "ORP", featureLayer: null },
{ layerID: "61a605dca69c4aa0ac1b3858ba328fd3", opacity: 1.0, name: "obceSouc", featureLayer: null }
] },
{ year: 1936, layers: [
{ layerID: "443709212b894e9297888b3194b51100", opacity: 1.0, name: "ORP", featureLayer: null },
{ layerID: "61a605dca69c4aa0ac1b3858ba328fd3", opacity: 1.0, name: "obceSouc", featureLayer: null }
] },
{ year: 1950, layers: [
{ layerID: "23bcd52310854d6185e5f22a4eca0303", opacity: 1.0, name: "ORP", featureLayer: null },
{ layerID: "61a605dca69c4aa0ac1b3858ba328fd3", opacity: 1.0, name: "obceSouc", featureLayer: null }
] },
{ year: 1981, layers: [
{ layerID: "401e9530ba074936800a8f596fc49d70", opacity: 1.0, name: "ORP", featureLayer: null },
{ layerID: "61a605dca69c4aa0ac1b3858ba328fd3", opacity: 1.0, name: "obceSouc", featureLayer: null }
] },
]
我有简单的输入元素来选择年份,当单击按钮时,图层也会更改。 该项目在这里: https ://www.pramenykrkonos.eu/wp-content/uploads/2022/06/index-3.html 它是捷克语 - 我需要为实际图层应用过滤器。
这是为每一层创建变量的地方:
const createFL = (layer) => {
if(layer.featureLayer !== null && layer.featureLayer !== undefined)
return;
layer.featureLayer = new FeatureLayer({ portalItem: {
id: layer.layerID,
opacity: layer.opacity !== undefined ? layer.opacity : 1.0,
visible: false,
} })
}
过滤器的表达式在这里定义并且应该在单击按钮“doBtn”时应用。
document.getElementById("doBtn").addEventListener("click",doQuery);
const attributeName = document.getElementById("attSelect");
const expressionSign = document.getElementById("signSelect");
const inputValue = document.getElementById("valSelect");
let expression;
function doQuery() {
expression = attributeName.value +
expressionSign.value +
"'"+inputValue.value+"'";
document.getElementById("printResults").innerHTML = expression;
featureLayer.definitionExpression = expression;
}
如果我理解这个问题,那么我想一个简单的解决方案是获取可见层并应用过滤器。 我猜,这种情况下的可见层是“当前”层。
如果是这种情况,那么您的功能将是这样的,
function doQuery() {
expression = attributeName.value +
expressionSign.value +
"'" + inputValue.value + "'";
document.getElementById("printResults").innerHTML = expression;
// get visible feature layers, and then apply filter
concatedLayers.filter(l => l.visible).forEach(l => l.definitionExpression = expression);
}
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