Question

我正在尝试使用OpenLayers 5在地图上添加卫星图像。

问题是我无法执行此操作，因为我刚刚找到了一种选项，可以在地图上通过图像范围（xmin，ymin，xmax，ymax）而不是边界框添加图像。图像应放在边框内。因此，图像失真了。

图像在JPG文件中（属性feature.properties.icon）。示例：http://exampleserver.com/220/063/353LGN00/353LGN00_thumb_large.jpg

我想要的结果是这样的：

我得到的结果是：

我将此代码添加到地图上的代码如下：

import ImageLayer from 'ol/layer/Image'
import Static from 'ol/source/ImageStatic'

...

this.olmap = new Map({
    target: 'map',
    layers: [
      baseLayerGroup, rasterLayerGroup, vectorLayer
    ],
    view: new View({
        projection: 'EPSG:4326',
        center: [ -45.8392, -3.65286 ],
        zoom: 8
    })
})

...

this.rasterLayerGroup.getLayers().push(
    new ImageLayer({
        source: new Static({
            url: feature.properties.icon,
            projection: 'EPSG:4326',
            imageExtent: [
              feature.properties.bl_longitude, feature.properties.bl_latitude,
              feature.properties.tr_longitude, feature.properties.tr_latitude
            ]  
        })
    })
)

有人会知道如何通过图像边界框，而不只是图像范围吗？

谢谢。

编辑1：迈克的解决方案

通过Mike的解决方案，我能够修复一些图像所存在的错误（在赤道线附近）。因此，他的回答解决了我的问题，并在我提出问题的那一刻将图像插入了我期望的更好的位置。

但是，这种解决方案对我来说适用于赤道线附近的图像。极点附近的图像保持扭曲（编辑2 ）。

我在下面发送一张图片，说明最终结果：

编辑2：新问题？

我正在测试一些图像，但发现了一个新错误。现在，我发现图像应该放在边框内。如果图像不能放入bbox中，它将保持扭曲，例如我在下面的插图中发送的打印内容。

该图像应与 [PS 1] 下的图像一样容纳在bbox中：

我认为这可能是重新投影的问题，但我不知道，因为视图投影和图像投影都是EPSG：4326。

我尝试遵循Openlayers网站上有关Raster Reprojection [1。]的说明，但是我无法复制它，因为正如我所说，两个投影（视图和图像）是相同的（或者应该相同）。）。

我在下面发送了GeoJSON，其中包含与上图有关的信息。可以在“ properties.icon”（http://www.dpi.inpe.br/newcatalog/tmp/MOD13Q1/2018/MOD13Q1.A2018017.h13v14.jpg）中找到该图像。 bbox坐标可在“ geometry.coordinates”或“ properties.bl_latitude”，“ properties.bl_longitude”，“ properties.br_latitude”等中找到。 “ bl”表示“左下”，“ br”表示“右下”，“ tl”表示“左上”，“ tr”表示“右上”。 “属性”中的这些坐标与“ geometry.coordinates”中的坐标相同。

{
  "geometry": {
    "coordinates": [
      [
        [
          -77.7862,
          -50
        ],
        [
          -100,
          -60
        ],
        [
          -80,
          -60
        ],
        [
          -62.229,
          -50
        ],
        [
          -77.7862,
          -50
        ]
      ]
    ],
    "type": "Polygon"
  },
  "properties": {
    "alternate": "http://www.dpi.inpe.br/opensearch/v2/granule.json?uid=MOD13Q1.A2018017.h13v14",
    "auxpath": null,
    "bitslips": null,
    "bl_latitude": -60,
    "bl_longitude": -100,
    "br_latitude": -60,
    "br_longitude": -80,
    "centerlatitude": -55,
    "centerlongitude": -80.0038,
    "centertime": null,
    "cloud": 0,
    "cloudcovermethod": "M",
    "dataset": "MOD13Q1",
    "date": "2018-01-17T00:00:00",
    "enclosure": [
      {
        "band": "evi",
        "radiometric_processing": "SR",
        "type": "MOSAIC",
        "url": "http://www.dpi.inpe.br/newcatalog/tmp/MOD13Q1/2018/MOD13Q1.A2018017.h13v14.006.2018033223827.hdf"
      },
      {
        "band": "ndvi",
        "radiometric_processing": "SR",
        "type": "MOSAIC",
        "url": "http://www.dpi.inpe.br/newcatalog/tmp/MOD13Q1/2018/MOD13Q1.A2018017.h13v14.006.2018033223827.hdf"
      },
      ...
    ],
    "icon": "http://www.dpi.inpe.br/newcatalog/tmp/MOD13Q1/2018/MOD13Q1.A2018017.h13v14.jpg",
    "id": "http://www.dpi.inpe.br/opensearch/v2/granule.json?uid=MOD13Q1.A2018017.h13v14",
    "orbit": 0,
    "path": 14,
    "provider": "OP_CBERS1",
    "row": 13,
    "satellite": "T1",
    "sensor": "MODIS",
    "title": "MOD13Q1.A2018017.h13v14",
    "tl_latitude": -50,
    "tl_longitude": -77.7862,
    "tr_latitude": -50,
    "tr_longitude": -62.229,
    "type": "IMAGES",
    "updated": "2018-03-01T18:51:56",
    "via": "http://www.dpi.inpe.br/opensearch/v2/metadata/MOD13Q1.A2018017.h13v14"
  },
  "type": "Feature"
}

有人会有新主意吗？

[PS 1]：：使图像适合bbox的原始代码是Leaflet代码[2.]，我将其发送至以下位置：

var map = L.map('map').setView([-15.22, -53.23], 5)

...

var anchor = [
    [feature.properties.tl_latitude, feature.properties.tl_longitude],
    [feature.properties.tr_latitude, feature.properties.tr_longitude],
    [feature.properties.br_latitude, feature.properties.br_longitude],
    [feature.properties.bl_latitude, feature.properties.bl_longitude]
]

layer._quicklook = L.imageTransform(feature.properties.icon, anchor).addTo(map)

[1。] https://openlayers.org/en/latest/doc/tutorials/raster-reprojection.html

[2。] https://github.com/ScanEx/Leaflet.imageTransform

Answer 1

如果坐标是照片的坐标，并且包含旋转照片的jpg在EPSG：4326中（即与子午线和平行线对齐），那么您需要一个包含照片所有角的边界框

import {boundingExtent} from 'ol/extent';

....

this.rasterLayerGroup.getLayers().push(
    new ImageLayer({
        source: new Static({
            url: feature.properties.icon,
            projection: 'EPSG:4326',
            imageExtent: boundingExtent([
              [feature.properties.bl_longitude, feature.properties.bl_latitude],
              [feature.properties.br_longitude, feature.properties.br_latitude],
              [feature.properties.tl_longitude, feature.properties.tl_latitude],
              [feature.properties.tr_longitude, feature.properties.tr_latitude]
            ])  
        })
    })
)

但是，最上面的屏幕截图本身已旋转了jpg。如果需要，则投影不是EPSG：4326，则需要定义一个自定义投影来处理旋转。

我设法缩小了距离，但是仅仅拉伸图像以使其适合多边形并不能像传单方法那样精确地对齐

var properties = {
    "bl_latitude": -60,
    "bl_longitude": -100,
    "br_latitude": -60,
    "br_longitude": -80,
    "centerlatitude": -55,
    "centerlongitude": -80.0038,
    "icon": "https://www.mikenunn.net/demo/MOD13Q1.A2018017.h13v14.jpg",
    "tl_latitude": -50,
    "tl_longitude": -77.7862,
    "tr_latitude": -50,
    "tr_longitude": -62.229,
};

function overlaySource ( properties ) {

    var projection = ol.proj.get('EPSG:3857');  // leaflet projection

    var extentSize = [0, 0, 4096, 4096];  // arbitary extent for the projection transforms
    var size0 = extentSize[2];
    var size1 = extentSize[3];

    var url = properties.icon;

    var bl = ol.proj.transform([properties.bl_longitude, properties.bl_latitude], 'EPSG:4326', projection);
    var tl = ol.proj.transform([properties.tl_longitude, properties.tl_latitude], 'EPSG:4326', projection);
    var br = ol.proj.transform([properties.br_longitude, properties.br_latitude], 'EPSG:4326', projection);
    var tr = ol.proj.transform([properties.tr_longitude, properties.tr_latitude], 'EPSG:4326', projection);

    function normalTransform(coordinates, output, dimensions) {
        var dims = dimensions || 2;
        for (var i=0; i<coordinates.length; i+=dims) {

            var left = bl[0] + (tl[0]-bl[0]) * coordinates[i+1]/size1;
            var right = br[0] + (tr[0]-br[0]) * coordinates[i+1]/size1;

            var top = tl[1] + (tr[1]-tl[1]) * coordinates[i]/size0;
            var bottom = bl[1] + (br[1]-bl[1]) * coordinates[i]/size0;

            var newCoordinates0 = left + (right-left) * coordinates[i]/size0;
            var newCoordinates1 = bottom + (top-bottom) * coordinates[i+1]/size1;

            c = ol.proj.transform([newCoordinates0, newCoordinates1], projection, 'EPSG:3857');

            //console.log(coordinates[i] + ' ' + coordinates[i+1] + ' ' + c[0] + ' ' + c[1]);

            coordinates[i] = c[0];
            coordinates[i+1] = c[1];

        }
        return coordinates;
    }

    function rotateTransform(coordinates, output, dimensions) {
        var dims = dimensions || 2;
        for (var i=0; i<coordinates.length; i+=dims) {

            c = ol.proj.transform([coordinates[i], coordinates[i+1]], 'EPSG:3857', projection);

            var left = bl[0] + (tl[0]-bl[0]) * (c[1]-bl[1]) /(tl[1]-bl[1]);
            var right = br[0] + (tr[0]-br[0]) * (c[1]-br[1]) /(tr[1]-br[1]);

            var top = tl[1] + (tr[1]-tl[1]) * (c[0]-tl[0])/(tr[0]-tl[0]);
            var bottom = bl[1] + (br[1]-bl[1]) * (c[0]-bl[0])/(br[0]-bl[0]);

            var newCoordinates0 = (c[0]-left)*size0/(right-left);
            var newCoordinates1 = (c[1]-bottom)*size1/(top-bottom);

            //console.log(coordinates[i] + ' ' + coordinates[i+1] + ' ' + newCoordinates0 + ' ' + newCoordinates1);

            coordinates[i] = newCoordinates0;
            coordinates[i+1] = newCoordinates1;

        }
        return coordinates;
    }

    var rotatedProjection = new ol.proj.Projection({
        code: 'EPSG:' + url + 'rotated',
        units: 'm',
        extent: extentSize
    });
    ol.proj.addProjection(rotatedProjection);

    ol.proj.addCoordinateTransforms('EPSG:3857', rotatedProjection,
        function(coordinate) {
            return rotateTransform(coordinate);
        },
        function(coordinate) {
            return normalTransform(coordinate);
        }
    );

    ol.proj.addCoordinateTransforms('EPSG:4326', rotatedProjection,
        function(coordinate) {
            return rotateTransform(ol.proj.transform(coordinate, "EPSG:4326", "EPSG:3857"));
        },
        function(coordinate) {
            return ol.proj.transform(normalTransform(coordinate), "EPSG:3857", "EPSG:4326");
        }
    );

    return new ol.source.ImageStatic({
        projection: rotatedProjection,
        imageExtent: extentSize,
        url: url
    });

}

var tileLayer = new ol.layer.Tile({
    source: new ol.source.XYZ({
        attributions: [
            'Powered by Esri',
            'Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community'
        ],
        //attributionsCollapsible: false,
        url: 'https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}',
        maxZoom: 23
    })
});

var imageLayer = new ol.layer.Image({
    source:  overlaySource( properties ),
    opacity: 0.7
})

var map = new ol.Map({
    layers: [tileLayer, imageLayer],
    target: 'map',
    logo: false,
    view: new ol.View()
});

var imageProj = imageLayer.getSource().getProjection();
map.getView().fit(ol.proj.transformExtent(imageProj.getExtent(), imageProj, map.getView().getProjection()), {constrainResolution: false});

html, body, .map {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
}

<link href="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/css/ol.css" rel="stylesheet" />
<script src="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/build/ol.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.5.0/proj4.js"></script>
<div id="map" class="map"></div>

这是我的KML方法，但这是将矩形简单旋转指定角度，而不是将其扭曲成只有两个边平行的四边形。

function kmlOverlaySource ( kmlExtent, // KMLs specify the extent the unrotated image would occupy
                            url,
                            rotation,
                            imageSize,
) {

    // calculate latitude of true scale of equidistant cylindrical projection based on pixels per degree on each axis

    proj4.defs('EPSG:' + url, '+proj=eqc +lat_ts=' +
                              (Math.acos((ol.extent.getHeight(kmlExtent)/imageSize[1])
                                        /(ol.extent.getWidth(kmlExtent)/imageSize[0]))*180/Math.PI) +
                              ' +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs');

    if (ol.proj.proj4 && ol.proj.proj4.register) { ol.proj.proj4.register(proj4); } // if OL5 register proj4

    // convert the extents to source projection coordinates

    var projection = ol.proj.get('EPSG:' + url);
    var projExtent = ol.proj.transformExtent(kmlExtent, 'EPSG:4326', projection);

    var angle = -rotation * Math.PI/180;

    function rotateTransform(coordinates, output, dimensions) {
        var dims = dimensions || 2;
        for (var i=0; i<coordinates.length; i+=dims) {
            var point = new ol.geom.Point([coordinates[i],coordinates[i+1]]);
            point.rotate(angle, ol.extent.getCenter(projExtent));
            var newCoordinates = point.getCoordinates();
            coordinates[i] = newCoordinates[0];
            coordinates[i+1] = newCoordinates[1];
        }
        return coordinates;
    }

    function normalTransform(coordinates, output, dimensions) {
        var dims = dimensions || 2;
        for (var i=0; i<coordinates.length; i+=dims) {
            var point = new ol.geom.Point([coordinates[i],coordinates[i+1]]);
            point.rotate(-angle, ol.extent.getCenter(projExtent));
            var newCoordinates = point.getCoordinates();
            coordinates[i] = newCoordinates[0];
            coordinates[i+1] = newCoordinates[1];
        }
        return coordinates;
    }

    var rotatedProjection = new ol.proj.Projection({
        code: 'EPSG:' + url + 'rotated',
        units: 'm',
        extent: projExtent
    });
    ol.proj.addProjection(rotatedProjection);

    ol.proj.addCoordinateTransforms('EPSG:4326', rotatedProjection,
        function(coordinate) {
            return rotateTransform(ol.proj.transform(coordinate, 'EPSG:4326', projection));
        },
        function(coordinate) {
            return ol.proj.transform(normalTransform(coordinate), projection, 'EPSG:4326');
        }
    );

    ol.proj.addCoordinateTransforms('EPSG:3857', rotatedProjection,
        function(coordinate) {
            return rotateTransform(ol.proj.transform(coordinate, 'EPSG:3857', projection));
        },
        function(coordinate) {
            return ol.proj.transform(normalTransform(coordinate), projection, 'EPSG:3857');
        }
    );

    return new ol.source.ImageStatic({
        projection: rotatedProjection,
        url: url,
        imageExtent: projExtent
    });

}

var tileLayer = new ol.layer.Tile({
    source: new ol.source.XYZ({
        attributions: [
            'Powered by Esri',
            'Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community'
        ],
        //attributionsCollapsible: false,
        url: 'https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}',
        maxZoom: 23
    })
});

// these would normally be parsed from a KML file
var kmlExtent = [8.433995415151397, 46.65804355828784, 9.144871415151389, 46.77980155828784];
var url = 'https://raw.githubusercontent.com/ReneNyffenegger/about-GoogleEarth/master/kml/the_png_says.png'
var rotation = 30;
var imageSize = [];

var img = document.createElement('img');
img.onload = imageLoaded;
img.src = url;

function imageLoaded() {

    imageSize[0] = img.width;
    imageSize[1] = img.height;

    var imageLayer = new ol.layer.Image({
        source: kmlOverlaySource(kmlExtent, url, rotation, imageSize),
    });

    var map = new ol.Map({
        layers: [tileLayer, imageLayer],
        target: 'map',
        logo: false,
        view: new ol.View()
    });

    var imageProj = imageLayer.getSource().getProjection();
    map.getView().fit(ol.proj.transformExtent(imageProj.getExtent(), imageProj, map.getView().getProjection()), {constrainResolution: false});

}

html, body, .map {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
}

<link href="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/css/ol.css" rel="stylesheet" />
<script src="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/build/ol.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.5.0/proj4.js"></script>
<div id="map" class="map"></div>

使用OpenLayers 5

1 个答案: