On you page - you have your template, and this template have nested divs, in which map div is included.
When you set 100% height, you have to set this value for each nested div, otherwise this divs is collapsed and you can't see your map div. You can red about 100% div height and nested divs on the net, it is not connected only for map. Read about this.
And structure of your nested divs you can see in browser by web console
As for my template
I create simple template without nested divs. There are only 3 div, for header (top position), content (content position) and footer (bottom position). Header and footer you can use for menu or for other cases, you can publish module there. For content - you can use it only for component.
Therefore, when you create map menu item, and assign template - you can see full screen
joomla.zhuk.cc/index.php/zhgooglemap-demo-feature-fullscreen