When showing a google map in jquery mobile it appears (after reading the forums) that code like the following is required:
There is an official example for this here: http://view.jquerymobile.com/master/demos/examples/maps/geolocation.php
HTML:
Map View
CSS:
.page-map, .ui-content, #map-canvas { width: 100%; height: 100%; padding: 0; }