Mapping with Drupal

Challenges of Web-Based Mapping

The difficulties of making a map to be used online can be grouped into a couple of areas: there are limits to how much data a web browser can display on a typical interactive map, and there are usability problems when trying to display large amounts of information on a map.

Browser Capabilities

Most interactive maps use JavaScript very heavily. The image tiles that make up the map are loaded using JavaScript as the user zooms in and out and moves around the map. The points, lines, and polygons displayed on the map are added with JavaScript (usually interacting with HTML Canvas or SVG). Even modern web browsers have a point at which they get overwhelmed and become unresponsive because the client cannot handle all of the processing. A good rule of thumb for the limitation of points (including vertices in a polygon) is around 200–500. But, as this is client-side processing, performance varies depending on the user’s browser and hardware, so you should take into account your audience when determining these limitations.

Note

There is no hard limitation, as the limitation comes from the client (the browser and hardware of the user’s computer, phone, tablet, etc.). Modern browsers, such as Chrome, can handle upwards of 10,000 points, while Internet Explorer 7 is more like 300. Unfortunately, there have been no benchmarks for this, as there are so many variables to consider.

Client-side clustering

One approach to lessen the load on the client is to use a form of ...