I am creating a web page that needs a map. I need to plot many data points (in several thousands) of longitude and latitude on a map and cannot find any sort of software or freeware that will allow me to do this. They have to be divided into different categories, thus requiring different pins to show them. Do you guys have any suggestion on this? I need something that is easy to plot those points, and easy to embed onto an existing page.
The best solution is using google maps and playing with this API. You can find more information here: https://developers.google.com/maps/
You can also try iMapBuilder Online which is a web based mapping software tool, and let you create interactive map quickly by importing longitude and latitude values from a Excel or CSV addresses file.