Is there a way to hide the selected object's origin in the 3D view? By default all unselected object's origins do not show, but even after deselecting everything with A A it still shows the active object's origin. I know the Only Render checkbox will hide all the origins, but in this case it hide...

As PeterT said. Start by enabling the ANT Landscape addon. Open the user preferences Ctrl Alt U, got to the Addons tab, search for "Landscape". Click on the check mark on the right, if it is not already enabled. Add a Landscape Shift A > Mesh > Landscape like the picture below. Add a Remesh mo...