Geographical Data Visualization in a Web Application

Question

I've got a request to implement a visualization service for geographical related data.

I have a list of Italian ZIP Codes (they are called CAP in Italian). I've already found a table which maps these ZIP codes to geographical coordinates (lat/long).

So, the data I have to visualize as map is structured the following way:

ZIPcode Latitude Longitude RequestCount
------- -------- --------- ------------

Is there an easy way (using a web service or implementing it myself using a component - preferably in .NET) for creating a map chart similar to the image i inserted below? It needn't to be that pretty and not necessarily geo-political.

I just need a indicator for every point which shows a smaller or bigger circle and next to it the value of RequestCount. I think this could be done either using the coordinates or, if there is some service which maps the Italian ZIP codes, using the ZIP code.

Thank you in advance!

alt text http://img515.imageshack.us/img515/3814/carsalesuh6.png

Answer 1

GeoNames offers a data set and open source libraries for geo mapping

Answer 2

Take a look at .net Charting and Chart FX Maps (I've never used these before).