我正在使用来自IGN Géoportail WMTS的瓷砖渲染背景地图为outlined in this example:
var resolutions = [];
var matrixIds = [];
var proj3857 = getProjection('EPSG:3857');
var maxResolution = getWidth(proj3857.getExtent()) / 256;
for (var i = 0; i < 18; i++) {
matrixIds[i] = i.toString();
resolutions[i] = maxResolution / Math.pow(2, i);
}
var tileGrid = new WMTSTileGrid({
origin: [-20037508, 20037508],
resolutions: resolutions,
matrixIds: matrixIds
});
var ign_source = new WMTS({
url: 'https://wxs.ign.fr/pratique/geoportail/wmts',
layer: 'GEOGRAPHICALGRIDSYSTEMS.MAPS',
matrixSet: 'PM',
format: 'image/jpeg',
projection: 'EPSG:3857',
tileGrid: tileGrid,
style: 'normal',
attributions: '<a href="http://www.geoportail.fr/" target="_blank">' +
'<img src="https://api.ign.fr/geoportail/api/js/latest/' +
'theme/geoportal/img/logo_gp.gif"></a>'
});
var ign = new TileLayer({
source: ign_source,
opacity: 0.7
});
在缩放级别12,地图显示我需要的详细信息:
但是,缩小到缩放级别13,磁贴切换到较少的细节,对于我的用例来说太少了:
有没有办法告诉OpenLayers将瓷砖缩放“锁定”为12,同时仍然允许缩放超过OpenLayers而不是WMTS渲染的阈值?
换句话说:让OpenLayers完成所有缩放,并始终从WMTS获得缩放级别12的细节图块。
谢谢你的帮助!
这会将tilegrid限制为缩放级别(矩阵id)13:
var tileGrid = new WMTSTileGrid({
origin: [-20037508, 20037508],
resolutions: resolutions.slice(13,14),
matrixIds: matrixIds.slice(13,14)
});