[GIS] How to fit an OpenLayers view to an extent that spans the map extent (wrap) or IDL

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How to fit the view to an extent that spans the map extent (wrap-point) or IDL?

Please excuse my semantics if they are incorrect, I'm new to GIS.

I've set up some code that does a zoom to extent based on these OpenLayers examples:

http://openlayers.org/en/latest/examples/center.html

http://openlayers.org/en/latest/examples/draw-features.html

The code (see below), works fine for extents that stay within the extents of the world map, e.g. Africa.

It does not work as I would like for my Pacific region, which spans the IDL and the point at which the map "wraps" in OpenLayers.

The actual behaviour is that the line between the 2 points goes "the long way", showing me almost the whole map, instead of the short way which gives only the Pacific. See screenshots after code sample.

var Pacific = {
            bottomLeft: [112.67578, -49.42705],
            topRight: [-125.85937, 45.78093]
        };

var Africa = {
            bottomLeft: [21.62109, -33.92741],
            topRight: [60.11719, 37.80327]
        };

var region = Pacific; //Africa;

myLib.zoomToExtent(region.bottomLeft, region.topRight, function (){;});

zoomToExtent: function (bottomLeftLonLat, topRightLonLat, onZoomCompleteCallback) {
        var map = _getMap(_domTarget);
        var view = map.getView();

        var size = /** @type {ol.Size} */ (map.getSize());

        var ptA = ol.proj.fromLonLat(bottomLeftLonLat, _defaultProjection);
        var ptB = ol.proj.fromLonLat(topRightLonLat, _defaultProjection);

        geometry = new ol.geom.Polygon(null);

        var start = ptA;
        var end = ptB;

        geometry.setCoordinates([
          [start, [start[0], end[1]], end, [end[0], start[1]], start]
        ]);

        view.fit(geometry, size, { padding: [1, 1, 1, 1], constrainResolution: false });

        _numTilesLoaded = 0;
        _setBaseLayerLoadedCallback(map, onZoomCompleteCallback);
}

Actual effect of the above code (not exact, for example):

Desired effect (not exact, for example):

Best Answer

I don't know if it's the correct way, but OL can simulate latitudes over 180 and below -180. Eg. you can modify the right longitude of your pacific region to 360-125.85937.

At least this works with extents. Here are examples:

Fitting to the West

Fitting to the East

Related Solutions

[GIS] openlayers 3 print via jsPDF

you can use window.print() in javascript to print screen

or

Export PDF example .map { max-width: 566px; } Page size A0 (slow) A1 A2 A3 A4 A5 (fast) Resolution 72 dpi (fast) 150 dpi 300 dpi (slow) Export PDF var raster = new ol.layer.Tile({ source: new ol.source.OSM() });

  var format = new ol.format.WKT();
  var feature = format.readFeature(
      'POLYGON((10.689697265625 -25.0927734375, 34.595947265625 ' +
          '-20.1708984375, 38.814697265625 -35.6396484375, 13.502197265625 ' +
          '-39.1552734375, 10.689697265625 -25.0927734375))');
  feature.getGeometry().transform('EPSG:4326', 'EPSG:3857');

  var vector = new ol.layer.Vector({
    source: new ol.source.Vector({
      features: [feature]
    })
  });


  var map = new ol.Map({
    layers: [raster, vector],
    target: 'map',
    controls: ol.control.defaults({
      attributionOptions: {
        collapsible: false
      }
    }),
    view: new ol.View({
      center: [0, 0],
      zoom: 2
    })
  });


  var dims = {
    a0: [1189, 841],
    a1: [841, 594],
    a2: [594, 420],
    a3: [420, 297],
    a4: [297, 210],
    a5: [210, 148]
  };

  var loading = 0;
  var loaded = 0;

  var exportButton = document.getElementById('export-pdf');

  exportButton.addEventListener('click', function() {

    exportButton.disabled = true;
    document.body.style.cursor = 'progress';

    var format = document.getElementById('format').value;
    var resolution = document.getElementById('resolution').value;
    var dim = dims[format];
    var width = Math.round(dim[0] * resolution / 25.4);
    var height = Math.round(dim[1] * resolution / 25.4);
    var size = /** @type {ol.Size} */ (map.getSize());
    var extent = map.getView().calculateExtent(size);

    var source = raster.getSource();

    var tileLoadStart = function() {
      ++loading;
    };

    var tileLoadEnd = function() {
      ++loaded;
      if (loading === loaded) {
        var canvas = this;
        window.setTimeout(function() {
          loading = 0;
          loaded = 0;
          var data = canvas.toDataURL('image/png');
          var pdf = new jsPDF('landscape', undefined, format);
          pdf.addImage(data, 'JPEG', 0, 0, dim[0], dim[1]);
          pdf.save('map.pdf');
          source.un('tileloadstart', tileLoadStart);
          source.un('tileloadend', tileLoadEnd, canvas);
          source.un('tileloaderror', tileLoadEnd, canvas);
          map.setSize(size);
          map.getView().fit(extent);
          map.renderSync();
          exportButton.disabled = false;
          document.body.style.cursor = 'auto';
        }, 100);
      }
    };

    map.once('postcompose', function(event) {
      source.on('tileloadstart', tileLoadStart);
      source.on('tileloadend', tileLoadEnd, event.context.canvas);
      source.on('tileloaderror', tileLoadEnd, event.context.canvas);
    });

    map.setSize([width, height]);
    map.getView().fit(extent);
    map.renderSync();

  }, false);
</script>

OpenLayers 4 – Selecting Features on Click in a List Using JavaScript

I never selected a feature programmatically from outside of my map-div, but after a little googling around, I found those two gis.stackexchange-Answers that might help you.

The first one points out how to select something in your map: By pushing a feature to the select-Collection:

The other one points out, how you find the feature you have to push (just comparing your clicked text with the properties of the feature):

Hope that points you in a direction that helps...

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