Question

For my Windows Phone Mango app, I want to make overlay a heatmap on Bing Maps, and a tile overlay seems the best way to do it. I’ve been having trouble finding any good documentation or code samples to work from. It seems like most people are pointing the tile source to a web service. I’d rather render the heatmap on the phone itself – is that possible?

Answer 1

One of the main reasons to use tilelayers to represent data on a map is that the computation and rendering involved in creating the layer is performed in advance, generally as a one-off or infrequent task. Then, at runtime, the only work the client needs to do is to retrieve the pre-rendered tile images from the server and display them straight on the map, which is a simple, low-resource activity.

Rendering tiles can be a resource-intensive task, both in terms of processing and memory usage – for example, I can only render about 3 tiles per second on a quadcore desktop machine with 8Gb RAM. Even if it’s technically possible to create the tiles dynamically on a handheld device, the performance is almost certainly going to be unacceptable for any user. You’ve also got the question of how you’re going to store the data from which the layer is created. Since you’re talking about plotting a heatmap, I’m guessing you have a reasonably large dataset of points – did you envisage these stored locally on the device, or retrieved over the network? (either will create different problems).

Basically, while it may be theoretically possible to create tile layers dynamically on the client, doing so would negate almost any benefit of using tilelayers in the first place, which is why you probably won’t find any code samples explaining how to do so. Perhaps you could explain your comment why you’d rather create the heatmap on the phone?

It’s pretty easy to create a server-side tile renderer using .NET or PHP that renders and server tile images to a Bing Maps client, or you can use an existing map rendering library such as mapnik.org or geoserver.org.