Plotting coordinates on map image

I need a function that can do the following: 1) Plot single longitude/latitude coordinates on a world map image (final output is to be an image, and no google maps please) 2) Plot multiple longitude/latitude coordinates on a world map image with lines joining the point up (as in point 1 and 2 will be connected, point 2 and 3 will also be connect etc) 3) If possible to do the above live as the data comes in asynchronously I have all the data of the longitude/latitude coordinates stored already and outputting correctly. all i need is the ability to be able to feed that off to a function which will plot and construct a new image with the points plotted. oh must be done in php. happy to install any sort of extension for the server to be compatible with this script.