Generally, in landscape photography you want as much of the photo in focus as possible, so a large depth of field is desirable. Like in the photo above.
This is achieved by having a small aperture, something like f/16 or higher (remember, the smaller the aperture, the larger the aperture number).
Even with a small aperture, parts of the photos may still not be 100% sharp. To help ensure that everything is sharp in a photo some photographers will do what is called focus stacking. This is where multiple photos with different points of focus are combined together to ensure all areas of the photos are sharp. Some modern cameras have focus stacking as a built-in feature.
At times, having a shallow (small) depth of field is desirable, like in the photo above. This is generally done to add some sort of artistic flair like in impressionistic landscape photos.