托管土地覆盖 ImageryTileLayer
此示例显示如何将托管 ImageryTileLayer 的实例图层添加到 MapView 中的地图。此示例中的 ImageryTileLayer 显示了美国的国家土地覆盖数据库 （NLCD） 2016 年土地覆被类型。切片影像图层可在 GeoScene Online 中发布和托管。这些图层是从一个或多个影像文件生成的影像服务。如果使用多个影像创建 ImageryTileLayer，则这些影像将一起镶嵌成一个影像。源图像和栅格文件在上传到 GeoScene Online 组织时将转换为云栅格格式 （CRF）。有关托管栅格数据的详细信息，请参阅发布托管影像图层文档。
工作原理
当应用程序启动时，UI 允许用户指定要显示的土地覆盖类型和视图的 spatialReference。当用户选择土地覆盖类型时，我们会更新图层的渲染器，以显示选定的土地覆盖类型，如下所示。土地覆盖类型显示在应用程序右侧的方解石单选按钮组中。
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<html>
<head>
<meta charset="utf-8" />
<meta
name="viewport"
content="initial-scale=1,maximum-scale=1,user-scalable=no"
/>
<title>Hosted Land Cover ImageryTileLayer | Sample | GeoScene API for JavaScript 4.22</title>
<script type="module" src="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.esm.js"></script>
<script nomodule="" src="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.js"></script>
<link rel="stylesheet" type="text/css"
href="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.css" />
<link rel="stylesheet" href="https://js.geoscene.cn/4.23/geoscene/themes/light/main.css" />
<script src="https://js.geoscene.cn/4.23/"></script>
<style>
html,
body,
#viewDiv {
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
#infoDiv {
position: absolute;
top: 10px;
right: 10px;
padding: 10px;
width: 200px;
height: 320px;
}
</style>
<script>
require([
"geoscene/Map",
"geoscene/views/MapView",
"geoscene/layers/ImageryTileLayer",
"geoscene/layers/FeatureLayer",
"geoscene/layers/GroupLayer",
"geoscene/renderers/UniqueValueRenderer",
"geoscene/renderers/support/UniqueValueInfo",
"geoscene/geometry/SpatialReference"
], (
Map,
MapView,
ImageryTileLayer,
FeatureLayer,
GroupLayer,
UniqueValueRenderer, UniqueValueInfo,
SpatialReference
) => (async () => {
let view, layer;
// drop down for changing view's spatial reference
const wkidSelect = document.getElementById("projectWKID");
wkidSelect.addEventListener("change", async () => {
const groupLayer = await createLayer();
recreateView(groupLayer);
});
// drop down for changing the land cover types
const landCoverTypeSelect = document.getElementById("landCoverTypeSelect");
landCoverTypeSelect.addEventListener("calciteRadioButtonGroupChange", (event) => {
if (!layer.loaded) {
return;
}
let renderer = layer.renderer.clone();
const value = event.detail;
renderer = changeLandCoverType(landTypes[value]);
layer.renderer = renderer;
});
// land cover types to set when user changes the land cover type
const landTypes = {
forests: {
categories: [
"Deciduous Forest",
"Evergreen Forest",
"Mixed Forest",
],
color: ["#006622", "#006622", "#006622", "#006622"]
},
developed: {
categories: [
"Developed, Open Space",
"Developed, Low Intensity",
"Developed, Medium Intensity",
"Developed, High Intensity"
],
color: ["#E5D0DD", "#E08B88", "#FF0000", "#A70000"]
},
crops: {
categories: ["Cultivated Crops"],
color: ["#A56400"]
},
hay: {
categories: ["Hay/Pasture"],
color: ["#D3F40E"]
},
wetlands: {
categories: [
"Woody Wetlands",
"Emergent Herbaceuous Wetlands"
],
color: ["#0073e6", "#0073e6"]
},
};
// create a group layer that contains the 2016 land cover types imagery layer
const groupLayer = await createLayer();
recreateView(groupLayer);
// this function creates a new instance of group and imagery layer whenever
// the app is loaded or the view projection changes
async function createLayer() {
document.getElementById("forests").checked = true;
// initialize the imagery layer with lerc format
const layer = new ImageryTileLayer({
url:
"https://tiledimageservices.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/NLCD_2016_Land_Cover_L48_20190424/ImageServer",
format: "lerc",
renderer: changeLandCoverType(landTypes.forests),
blendMode: "color-dodge",
effect: "bloom(0.5, 0.5px, 20%) drop-shadow(1px, 1px, 1px, grey)"
});
const groupLayer = new GroupLayer({
layers: [layer],
title: "Forested areas 2016",
});
return groupLayer.load();
}
// this function is called whenever user changes the land cover type
// from the drop down. It creates a unique value renderer for the
// land cover type the user selected.
function changeLandCoverType(landType) {
const uvr = new UniqueValueRenderer({
field: "NLCD_Land",
uniqueValueInfos: []
});
landType.categories.forEach((value, i) => {
const uniqueValue = new UniqueValueInfo({
value,
symbol: {
type: "simple-fill",
color: landType.color[i]
}
});
uvr.uniqueValueInfos.push(uniqueValue);
});
return uvr;
}
// Called when the app loads or when the user changes the view spatial reference
async function recreateView(groupLayer) {
const viewSpatialReference = new SpatialReference({
wkid: wkidSelect.value
});
// preset center points for the view in different spatial references
const centerPoints = {
4326: {
x: -98,
y: 35
},
102003: {
x: 0,
y: 0
},
102100: {
x: -10998374,
y: 4906766
}
};
let centerPoint = {
x: centerPoints[wkidSelect.value].x,
y: centerPoints[wkidSelect.value].y,
spatialReference: viewSpatialReference
};
// this states layer will be used as the basemap
const statesLayer = new FeatureLayer({
url:
"https://sampleserver6.geosceneonline.cn/arcgis/rest/services/USA/MapServer/2",
renderer: {
type: "simple",
symbol: {
type: "simple-fill",
color: "#505050",
outline: {
color: "#DCDCDC",
width: "0.5px"
}
}
},
spatialReference: viewSpatialReference,
effect: "drop-shadow(-10px, 10px, 6px gray)"
});
const map = new Map({
basemap: {
baseLayers: [
statesLayer
]
},
layers: [groupLayer]
});
if (view) {
view.map.removeAll();
view.container = null;
view.map = null;
}
view = new MapView({
container: "viewDiv",
map: map,
spatialReference: viewSpatialReference,
center: centerPoint,
scale: 19975114,
background: {
color: "#F5F5F5"
}
});
// get a reference to the land cover imagery layer
layer = groupLayer.layers.getItemAt(0);
}
})());
</script>
</head>
<body>
<div id="viewDiv"></div>
<div id="infoDiv" class="geoscene-widget">
<h4 id="titleText" class="esri-widget__heading esri-editor__title">Land
cover types - 2016</h4><br>
<div class="geoscene-widget">
<calcite-label><b>Select land type:</b>
<calcite-radio-button-group name="Select land type" layout="vertical"
id="landCoverTypeSelect" scale="s">
<calcite-label layout="inline"><calcite-radio-button id="forests"
value="forests"
checked></calcite-radio-button>Forested Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button
value="developed"></calcite-radio-button>Developed Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button value="crops"></calcite-radio-button>Cultivated
Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button value="hay"></calcite-radio-button>Hay/Pasture
Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button
value="wetlands"></calcite-radio-button>Wetlands</calcite-label>
</calcite-radio-button-group>
</calcite-label>
</div>
<div id="projectionDiv" class="geoscene-widget">
<p><b>Change view's projection:</b></p>
<select id="projectWKID" class="esri-input esri-select">
<option value="102003" selected>Albers Equal Area</option>
<option value="102100">Web Mercator</option>
<option value="4326">WGS 84</option>
</select>
</div>
</div>
</body>
</html>当用户选择一个空间参照时，我们用指定的 spatialReference 重新加载视图，如下所示：
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<html>
<head>
<meta charset="utf-8" />
<meta
name="viewport"
content="initial-scale=1,maximum-scale=1,user-scalable=no"
/>
<title>Hosted Land Cover ImageryTileLayer | Sample | GeoScene API for JavaScript 4.22</title>
<script type="module" src="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.esm.js"></script>
<script nomodule="" src="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.js"></script>
<link rel="stylesheet" type="text/css"
href="https://js.arcgis.com/calcite-components/1.0.0-beta.69/calcite.css" />
<link rel="stylesheet" href="https://js.geoscene.cn/4.23/geoscene/themes/light/main.css" />
<script src="https://js.geoscene.cn/4.23/"></script>
<style>
html,
body,
#viewDiv {
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
#infoDiv {
position: absolute;
top: 10px;
right: 10px;
padding: 10px;
width: 200px;
height: 320px;
}
</style>
<script>
require([
"geoscene/Map",
"geoscene/views/MapView",
"geoscene/layers/ImageryTileLayer",
"geoscene/layers/FeatureLayer",
"geoscene/layers/GroupLayer",
"geoscene/renderers/UniqueValueRenderer",
"geoscene/renderers/support/UniqueValueInfo",
"geoscene/geometry/SpatialReference"
], (
Map,
MapView,
ImageryTileLayer,
FeatureLayer,
GroupLayer,
UniqueValueRenderer, UniqueValueInfo,
SpatialReference
) => (async () => {
let view, layer;
// drop down for changing view's spatial reference
const wkidSelect = document.getElementById("projectWKID");
wkidSelect.addEventListener("change", async () => {
const groupLayer = await createLayer();
recreateView(groupLayer);
});
// drop down for changing the land cover types
const landCoverTypeSelect = document.getElementById("landCoverTypeSelect");
landCoverTypeSelect.addEventListener("calciteRadioButtonGroupChange", (event) => {
if (!layer.loaded) {
return;
}
let renderer = layer.renderer.clone();
const value = event.detail;
renderer = changeLandCoverType(landTypes[value]);
layer.renderer = renderer;
});
// land cover types to set when user changes the land cover type
const landTypes = {
forests: {
categories: [
"Deciduous Forest",
"Evergreen Forest",
"Mixed Forest",
],
color: ["#006622", "#006622", "#006622", "#006622"]
},
developed: {
categories: [
"Developed, Open Space",
"Developed, Low Intensity",
"Developed, Medium Intensity",
"Developed, High Intensity"
],
color: ["#E5D0DD", "#E08B88", "#FF0000", "#A70000"]
},
crops: {
categories: ["Cultivated Crops"],
color: ["#A56400"]
},
hay: {
categories: ["Hay/Pasture"],
color: ["#D3F40E"]
},
wetlands: {
categories: [
"Woody Wetlands",
"Emergent Herbaceuous Wetlands"
],
color: ["#0073e6", "#0073e6"]
},
};
// create a group layer that contains the 2016 land cover types imagery layer
const groupLayer = await createLayer();
recreateView(groupLayer);
// this function creates a new instance of group and imagery layer whenever
// the app is loaded or the view projection changes
async function createLayer() {
document.getElementById("forests").checked = true;
// initialize the imagery layer with lerc format
const layer = new ImageryTileLayer({
url:
"https://tiledimageservices.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/NLCD_2016_Land_Cover_L48_20190424/ImageServer",
format: "lerc",
renderer: changeLandCoverType(landTypes.forests),
blendMode: "color-dodge",
effect: "bloom(0.5, 0.5px, 20%) drop-shadow(1px, 1px, 1px, grey)"
});
const groupLayer = new GroupLayer({
layers: [layer],
title: "Forested areas 2016",
});
return groupLayer.load();
}
// this function is called whenever user changes the land cover type
// from the drop down. It creates a unique value renderer for the
// land cover type the user selected.
function changeLandCoverType(landType) {
const uvr = new UniqueValueRenderer({
field: "NLCD_Land",
uniqueValueInfos: []
});
landType.categories.forEach((value, i) => {
const uniqueValue = new UniqueValueInfo({
value,
symbol: {
type: "simple-fill",
color: landType.color[i]
}
});
uvr.uniqueValueInfos.push(uniqueValue);
});
return uvr;
}
// Called when the app loads or when the user changes the view spatial reference
async function recreateView(groupLayer) {
const viewSpatialReference = new SpatialReference({
wkid: wkidSelect.value
});
// preset center points for the view in different spatial references
const centerPoints = {
4326: {
x: -98,
y: 35
},
102003: {
x: 0,
y: 0
},
102100: {
x: -10998374,
y: 4906766
}
};
let centerPoint = {
x: centerPoints[wkidSelect.value].x,
y: centerPoints[wkidSelect.value].y,
spatialReference: viewSpatialReference
};
// this states layer will be used as the basemap
const statesLayer = new FeatureLayer({
url:
"https://sampleserver6.geosceneonline.cn/arcgis/rest/services/USA/MapServer/2",
renderer: {
type: "simple",
symbol: {
type: "simple-fill",
color: "#505050",
outline: {
color: "#DCDCDC",
width: "0.5px"
}
}
},
spatialReference: viewSpatialReference,
effect: "drop-shadow(-10px, 10px, 6px gray)"
});
const map = new Map({
basemap: {
baseLayers: [
statesLayer
]
},
layers: [groupLayer]
});
if (view) {
view.map.removeAll();
view.container = null;
view.map = null;
}
view = new MapView({
container: "viewDiv",
map: map,
spatialReference: viewSpatialReference,
center: centerPoint,
scale: 19975114,
background: {
color: "#F5F5F5"
}
});
// get a reference to the land cover imagery layer
layer = groupLayer.layers.getItemAt(0);
}
})());
</script>
</head>
<body>
<div id="viewDiv"></div>
<div id="infoDiv" class="geoscene-widget">
<h4 id="titleText" class="esri-widget__heading esri-editor__title">Land
cover types - 2016</h4><br>
<div class="geoscene-widget">
<calcite-label><b>Select land type:</b>
<calcite-radio-button-group name="Select land type" layout="vertical"
id="landCoverTypeSelect" scale="s">
<calcite-label layout="inline"><calcite-radio-button id="forests"
value="forests"
checked></calcite-radio-button>Forested Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button
value="developed"></calcite-radio-button>Developed Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button value="crops"></calcite-radio-button>Cultivated
Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button value="hay"></calcite-radio-button>Hay/Pasture
Areas</calcite-label>
<calcite-label layout="inline"><calcite-radio-button
value="wetlands"></calcite-radio-button>Wetlands</calcite-label>
</calcite-radio-button-group>
</calcite-label>
</div>
<div id="projectionDiv" class="geoscene-widget">
<p><b>Change view's projection:</b></p>
<select id="projectWKID" class="esri-input esri-select">
<option value="102003" selected>Albers Equal Area</option>
<option value="102100">Web Mercator</option>
<option value="4326">WGS 84</option>
</select>
</div>
</div>
</body>
</html>