i have to resize the gmap component. But i do not know how. The gmap component is missing a size(width,height)attribute, and the google map api docu says this about size:
Sets the size in pixels of the map. The container that is passed to the map constructor will be resized to the given size. By default, the map will assume the size of its container.
Found it. The first time, before writing this post, it was not working. The solution can be found in the richfaces demo of gmap
<rich:gmap oninit="initialize();" lng="11.4419" lat="49.1419" zoom="3" style="width:800px;height:400px">