Resizable Markers

A quick example demonstrating the use of "show" event handlers and reshow, which allows you to restyle GeoJSON features dynamically from an external event. In this example, you can use the jQuery UI slider in the top-left corner to resize the points.

<!DOCTYPE html>
<html>
  <head>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/gh/simplegeo/polymaps/v2.3.0/polymaps.min.js"></script>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/gh/simplegeo/polymaps/v2.3.0/lib/crimespotting/crimespotting.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/protovis/3.3.1/protovis.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/protovis/3.3.1/protovis.min.js"></script>
    <style type="text/css">

@import url("https://cdn.rawgit.com/simplegeo/polymaps/v2.3.0/examples/example.css");
@import url("https://cdn.rawgit.com/protovis/protovis/v3.3.1/examples/slider/ui-lightness/jquery-ui-1.8rc3.custom.css");

html, body {
  height: 100%;
  background: #E6E6E6;
}

svg {
  display: block;
}

.layer circle {
  fill: lightcoral;
  fill-opacity: .5;
  stroke: brown;
}

#slider {
  position: absolute;
  top: 10px;
  left: 10px;
  width: 300px;
  height: 20px;
  display: block;
  background: #ccc;
}

.ui-slider {
  font-size: 10px;
  margin-top: 5px;
}

.ui-state-focus {
  outline: none;
}

</style>
  </head>
  <body>
    <script type="text/javascript">

var po = org.polymaps;

var r = 4.5;

var map = po.map()
    .container(document.body.appendChild(po.svg("svg")))
    .center({lat: 37.787, lon: -122.228})
    .zoomRange([10, 16])
    .add(po.interact());

map.add(po.image()
    .url(po.url("https://{S}tile.cloudmade.com"
    + "/1a1b06b230af4efdbb989ea99e9841af" // https://cloudmade.com/register
    + "/998/256/{Z}/{X}/{Y}.png")
    .hosts(["a.", "b.", "c.", ""])));

map.add(geoJson = po.geoJson()
    .url(crimespotting("https://oakland.crimespotting.org"
        + "/crime-data"
        + "?count=100"
        + "&format=json"
        + "&bbox={B}"
        + "&dstart=2010-04-01"
        + "&dend=2010-04-01"))
    .on("show", show)
    .clip(false)
    .scale("fixed")
    .zoom(12));

/* Resize the GeoJSON points! */
function show(e) {
  for (var i = 0; i < e.features.length; i++) {
    e.features[i].element.setAttribute("r", r);
  }
}

</script>
    <div id="slider"></div>
    <script type="text/javascript">

$("#slider").slider({
  min: 0, max: 1000, value: r * r, slide: function(e, ui) {
    r = Math.sqrt(ui.value);
    geoJson.reshow();
  }
});

</script>
    <span id="copy">
      &copy; 2010
      <a href="https://www.cloudmade.com/">CloudMade</a>,
      <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors,
      <a href="https://creativecommons.org/licenses/by-sa/2.0/">CCBYSA</a>.
    </span>
  </body>
</html>

Updated missing url https://cdn.rawgit.com/simplegeo/polymaps/v2.3.0/polymaps.min.js to https://cdn.jsdelivr.net/gh/simplegeo/polymaps/v2.3.0/polymaps.min.js

Updated missing url https://cdn.rawgit.com/simplegeo/polymaps/v2.3.0/lib/crimespotting/crimespotting.js to https://cdn.jsdelivr.net/gh/simplegeo/polymaps/v2.3.0/lib/crimespotting/crimespotting.js

Updated missing url https://cdn.rawgit.com/protovis/protovis/v3.3.1/examples/jquery-1.4.2.min.js to https://cdnjs.cloudflare.com/ajax/libs/protovis/3.3.1/protovis.min.js

Updated missing url https://cdn.rawgit.com/protovis/protovis/v3.3.1/examples/slider/jquery-ui-1.8rc3.custom.min.js to https://cdnjs.cloudflare.com/ajax/libs/protovis/3.3.1/protovis.min.js

https://cdn.rawgit.com/simplegeo/polymaps/v2.3.0/polymaps.min.js

https://cdn.rawgit.com/simplegeo/polymaps/v2.3.0/lib/crimespotting/crimespotting.js

https://cdn.rawgit.com/protovis/protovis/v3.3.1/examples/jquery-1.4.2.min.js

https://cdn.rawgit.com/protovis/protovis/v3.3.1/examples/slider/jquery-ui-1.8rc3.custom.min.js