[Talk-it] Openlayers in val di ledro dove siamo arrivati

Sat Dec 6 16:50:44 GMT 2008

Ad oggi sono riuscito a pubblicare questo

http://www.icvallediledro.it/OpenStreetLedro/OpenStreetLedro.htm

"brutalmente scopiazzato" da http://cortesi.com/sapere_libera_tutti/

avrei bisogno di ottenere però una carta che parta da così

http://www.openstreetmap.org/?lat=45.8865&lon=10.7371&zoom=13&layers=B000FTF

e riesca ad arrivare a questo ingrandimento 

http://www.openstreetmap.org/?lat=45.89595&lon=10.717655&zoom=18&layers=B000FTF

(credo di aver capito che si tratta di zoom dal 13 al 18)

sulla quale posizionare i punti rilevati dai miei alunni.

mi sembra di capire che devo agire su parametri quali maxResolution ma non ne vengo a capo

il "mio" (grazie a Simone a Cortesi) .html è questo sotto. Dove devo agire?
Grazie matteo

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>

   <link rel="stylesheet" href="2style.css" type="text/css" />
        <link rel="stylesheet" href="framedCloud.css" type="text/css" />
    <link rel="stylesheet" href="style.css" type="text/css" />

    <style type="text/css">
        #map {
            width: 100%;
            height: 90%;
            border: 1px solid black;
        }
        .olPopup p { margin:0px; font-size: .9em;}
        .olPopup h2 { font-size:1.2em; }
    </style>
    <script src="http://openlayers.org/api/OpenLayers.js"></script>

    <script type="text/javascript">
        var lon = 9;
        var lat = 45;
        var zoom = 8;
        var map, layer;

        function init(){
            var options = {
                projection: new OpenLayers.Projection("EPSG:900913"),
                displayProjection: new OpenLayers.Projection("EPSG:4326"),
                units: "m",
                maxResolution: 156543.0339,
		maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34,
                                                 20037508.34, 20037508.34)
            };
            map = new OpenLayers.Map('map', options);
            var mapnik = new OpenLayers.Layer.TMS(
                "OpenStreetMap (Mapnik)",
                "http://tile.openstreetmap.org/",
                {
                    type: 'png', getURL: osm_getTileURL,
                    displayOutsideMaxExtent: true,
                    attribution: '<a href="http://www.openstreetmap.org/">OpenStreetMap</a>'
                }
            );
            map.addLayer(mapnik);
            map.addLayer(new OpenLayers.Layer.GML("KML", "valdiledro1.kml", 
               {
                format: OpenLayers.Format.KML, 
                projection: map.displayProjection,
                formatOptions: {
                  extractStyles: true, 
                  extractAttributes: true
                }
               }));
             selectControl = new OpenLayers.Control.SelectFeature(map.layers[1],
                {onSelect: onFeatureSelect, onUnselect: onFeatureUnselect});

            map.addControl(selectControl);
            selectControl.activate();   
            map.zoomToExtent(new OpenLayers.Bounds(6.45,36.3,18.85,47.2).transform(map.displayProjection, map.projection));
        }
        function onPopupClose(evt) {
            selectControl.unselect(selectedFeature);
        }
        function onFeatureSelect(feature) {
            selectedFeature = feature;
            popup = new OpenLayers.Popup.FramedCloud("chicken", 
                                     feature.geometry.getBounds().getCenterLonLat(),
                                     new OpenLayers.Size(220,220),
                                     "<h2>"+feature.attributes.name + "</h2>" + feature.attributes.description,
                                     null, true, onPopupClose);
            feature.popup = popup;
            map.addPopup(popup);
        }
        function onFeatureUnselect(feature) {
            map.removePopup(feature.popup);
            feature.popup.destroy();
            feature.popup = null;
        }
        function osm_getTileURL(bounds) {
            var res = this.map.getResolution();
            var x = Math.round((bounds.left - this.maxExtent.left) / (res * this.tileSize.w));
            var y = Math.round((this.maxExtent.top - bounds.top) / (res * this.tileSize.h));
            var z = this.map.getZoom();
            var limit = Math.pow(2, z);

            if (y < 0 || y >= limit) {
                return OpenLayers.Util.getImagesLocation() + "404.png";
            } else {
                x = ((x % limit) + limit) % limit;
                return this.url + z + "/" + x + "/" + y + "." + this.type;
            }
        }
    </script>

<title>Openstreetledro!</title>

  </head>
  <body onload="init()">
      <h1 id="title">Openstreetledro!</h1>

    <div id="map" class="smallmap"></div>

    <div id="docs"></div>
  </body>
</html>