php - 如何显示 ol-3 层切换器
问题描述
我正在开发 GIS,但无法显示图层切换器。在这种情况下,我使用了 Open Layers 3。
map = new ol.Map({
controls: ol.control.defaults({
attribution: false
}).extend([mousePositionControl,zoomslider]),
target: document.getElementById('map'),
layers: [
new ol.layer.Group({
'title': 'BaseMaps',
layers: [
new ol.layer.Tile({
title: 'RoadMaps',
source: new ol.source.OSM({
url: 'http://mt{0-3}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}',
attributions: [
new ol.Attribution({ html: '© Google' }),
new ol.Attribution({ html: '<a href="https://developers.google.com/maps/terms">Terms of Use.</a>' })
]
})
}),
new ol.layer.Tile({
title: 'Satelite',
type: 'base',
visible: false,
source: new ol.source.OSM({
url: 'http://mt{0-3}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}',
attributions: [
new ol.Attribution({ html: '© Google' }),
new ol.Attribution({ html: '<a href="https://developers.google.com/maps/terms">Terms of Use.</a>' })
]
})
}),
new ol.layer.Tile({
title: 'OSM',
type: 'base',
visible: true,
source: new ol.source.OSM()
})
]
peta_highlight,
layers['layer_kategori'],
})
],
view: new ol.View({
projection: "EPSG:3857",
})
});
layerSwitcher = new ol.control.LayerSwitcher({
tipLabel: 'Légende' // Optional label for button
});
map.addControl(layerSwitcher);
此时我的代码仍然无法正常工作,这三张地图无法在我的网站上显示。
解决方案
假设您已正确包含图层切换器库,那么导致问题的不是图层切换器,而是您定义地图的方式中的一堆错误。
前面少了一个逗号peta_higlight
,layers['layer_kategori'],
没有任何意义。
ol.View
要求您添加中心和分辨率/缩放。
以下代码应该为您解决这些问题
map = new ol.Map({
controls: ol.control.defaults({
attribution: false
}).extend([new ol.control.MousePosition, new ol.control.ZoomSlider]),
target: document.getElementById("map"),
layers: [new ol.layer.Group({
title: "BaseMaps",
layers: [
new ol.layer.Tile({
title: "RoadMaps",
source: new ol.source.OSM({
url: "http://mt{0-3}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}",
attributions: [new ol.Attribution({
html: "© Google"
}), new ol.Attribution({
html: '<a href="https://developers.google.com/maps/terms">Terms of Use.</a>'
})]
})
}),
new ol.layer.Tile({
title: "Satelite",
type: "base",
visible: false,
source: new ol.source.OSM({
url: "http://mt{0-3}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}",
attributions: [new ol.Attribution({
html: "© Google"
}), new ol.Attribution({
html: '<a href="https://developers.google.com/maps/terms">Terms of Use.</a>'
})]
})
}),
new ol.layer.Tile({
title: "OSM",
type: "base",
visible: true,
source: new ol.source.OSM()
}), peta_highlight
]
})],
view: new ol.View({
center: [0, 0],
zoom: 5,
projection: 'EPSG:3857'
})
});
layerSwitcher = new ol.control.LayerSwitcher({
tipLabel: 'Légende' // Optional label for button
});
map.addControl(layerSwitcher);