Reprojection with EPSG.io Search

This example uses OpenLayers v4.0.1. The latest is v.

#### Reprojection with EPSG.io Search

Search projection:
Render reprojection edges

Demonstrates client-side raster reprojection of OSM to arbitrary projection

This example shows client-side raster reprojection capabilities from OSM (EPSG:3857) to arbitrary projection by searching in EPSG.io database.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.extent
,
- ol.layer.Tile
,
- ol.proj
,
- ol.source.OSM
,
- ol.source.TileImage

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Reprojection with EPSG.io Search Demonstrates client-side raster reprojection of OSM to arbitrary projection var map = new ol.Map({ layers: [ new ol.layer.Tile({ source: new ol.source.OSM() }) ], target: 'map', view: new ol.View({ projection: 'EPSG:3857', center: [0, 0], zoom: 1 }) }); var queryInput = document.getElementById('epsg-query'); var searchButton = document.getElementById('epsg-search'); var resultSpan = document.getElementById('epsg-result'); var renderEdgesCheckbox = document.getElementById('render-edges'); function setProjection(code, name, proj4def, bbox) { if (code === null || name === null || proj4def === null || bbox === null) { resultSpan.innerHTML = 'Nothing usable found, using EPSG:3857...'; map.setView(new ol.View({ projection: 'EPSG:3857', center: [0, 0], zoom: 1 })); return; } resultSpan.innerHTML = '(' + code + ') ' + name; var newProjCode = 'EPSG:' + code; proj4.defs(newProjCode, proj4def); var newProj = ol.proj.get(newProjCode); var fromLonLat = ol.proj.getTransform('EPSG:4326', newProj); // very approximate calculation of projection extent var extent = ol.extent.applyTransform( [bbox[1], bbox[2], bbox[3], bbox[0]], fromLonLat); newProj.setExtent(extent); var newView = new ol.View({ projection: newProj }); map.setView(newView); newView.fit(extent); } function search(query) { resultSpan.innerHTML = 'Searching ...'; fetch('https://epsg.io/?format=json&q=' + query).then(function(response) { return response.json(); }).then(function(json) { var results = json['results']; if (results && results.length > 0) { for (var i = 0, ii = results.length; i < ii; i++) { var result = results[i]; if (result) { var code = result['code'], name = result['name'], proj4def = result['proj4'], bbox = result['bbox']; if (code && code.length > 0 && proj4def && proj4def.length > 0 && bbox && bbox.length == 4) { setProjection(code, name, proj4def, bbox); return; } } } } setProjection(null, null, null, null); }); } /** * Handle click event. * @param {Event} event The event. */ searchButton.onclick = function(event) { search(queryInput.value); event.preventDefault(); }; /** * Handle change event. */ renderEdgesCheckbox.onchange = function() { map.getLayers().forEach(function(layer) { if (layer instanceof ol.layer.Tile) { var source = layer.getSource(); if (source instanceof ol.source.TileImage) { source.setRenderReprojectionEdges(renderEdgesCheckbox.checked); } } }); }; <div id="map" class="map"></div> <form class="form-inline"> <label for="epsg-query">Search projection:</label> <input type="text" id="epsg-query" placeholder="4326, 27700, US National Atlas, Swiss, France, ..." class="form-control" size="50" /> <button id="epsg-search" class="btn">Search</button> <span id="epsg-result"></span> <div> <label for="render-edges"> Render reprojection edges <input type="checkbox" id="render-edges"> </label> </div> </form>

    <!DOCTYPE html>
    <html>
      <head>
        <title>Reprojection with EPSG.io Search</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
        <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
        <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
        <script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.15/proj4.js"></script>
      </head>
      <body>
        <div id="map" class="map"></div>
        <form class="form-inline">
          <label for="epsg-query">Search projection:</label>
          <input type="text" id="epsg-query" placeholder="4326, 27700, US National Atlas, Swiss, France, ..." class="form-control" size="50" />
          <button id="epsg-search" class="btn">Search</button>
          <span id="epsg-result"></span>
          <div>
            <label for="render-edges">
              Render reprojection edges
              <input type="checkbox" id="render-edges">
            </label>
          </div>
        </form>
        <script>
          var map = new ol.Map({
            layers: [
              new ol.layer.Tile({
                source: new ol.source.OSM()
              })
            ],
            target: 'map',
            view: new ol.View({
              projection: 'EPSG:3857',
              center: [0, 0],
              zoom: 1
            })
          });

          var queryInput = document.getElementById('epsg-query');
          var searchButton = document.getElementById('epsg-search');
          var resultSpan = document.getElementById('epsg-result');
          var renderEdgesCheckbox = document.getElementById('render-edges');

          function setProjection(code, name, proj4def, bbox) {
            if (code === null || name === null || proj4def === null || bbox === null) {
              resultSpan.innerHTML = 'Nothing usable found, using EPSG:3857...';
              map.setView(new ol.View({
                projection: 'EPSG:3857',
                center: [0, 0],
                zoom: 1
              }));
              return;
            }

            resultSpan.innerHTML = '(' + code + ') ' + name;

            var newProjCode = 'EPSG:' + code;
            proj4.defs(newProjCode, proj4def);
            var newProj = ol.proj.get(newProjCode);
            var fromLonLat = ol.proj.getTransform('EPSG:4326', newProj);

            // very approximate calculation of projection extent
            var extent = ol.extent.applyTransform(
                [bbox[1], bbox[2], bbox[3], bbox[0]], fromLonLat);
            newProj.setExtent(extent);
            var newView = new ol.View({
              projection: newProj
            });
            map.setView(newView);
            newView.fit(extent);
          }

          function search(query) {
            resultSpan.innerHTML = 'Searching ...';
            fetch('https://epsg.io/?format=json&q=' + query).then(function(response) {
              return response.json();
            }).then(function(json) {
              var results = json['results'];
              if (results && results.length > 0) {
                for (var i = 0, ii = results.length; i < ii; i++) {
                  var result = results[i];
                  if (result) {
                    var code = result['code'], name = result['name'],
                        proj4def = result['proj4'], bbox = result['bbox'];
                    if (code && code.length > 0 && proj4def && proj4def.length > 0 &&
                        bbox && bbox.length == 4) {
                      setProjection(code, name, proj4def, bbox);
                      return;
                    }
                  }
                }
              }
              setProjection(null, null, null, null);
            });
          }

          /**
           * Handle click event.
           * @param {Event} event The event.
           */
          searchButton.onclick = function(event) {
            search(queryInput.value);
            event.preventDefault();
          };

          /**
           * Handle change event.
           */
          renderEdgesCheckbox.onchange = function() {
            map.getLayers().forEach(function(layer) {
              if (layer instanceof ol.layer.Tile) {
                var source = layer.getSource();
                if (source instanceof ol.source.TileImage) {
                  source.setRenderReprojectionEdges(renderEdgesCheckbox.checked);
                }
              }
            });
          };
        </script>
      </body>
    </html>