In Google Earth you can make the landscape look more rugged and dramatic by increasing Vertical Exaggeration i.e. by increasing the vertical scale relative to the horizontal scale of the map. It is a common technique used to bring out subtleties in topography and to accentuate relief.
Perspective plays an important role in our experience of relief. A dropped coin or a small object is easier to find if you lie flat on the floor and bring your eye level as close to the floor as possible. You can get the same effect by using the tilt function in Google Earth. In his book on World War 1 To End All Wars Adam Hochschild describes one such example of vertical exaggeration or perception of relief experienced by soldiers looking out from their trenches into the open countryside:
From his Fresh Air Interview with Terry Gross -
I also went to some of these battlefields because I always love to see the places where the history that I'm writing about took place, and you learned something there too. One thing that struck me for instance, I went to a place called High Wood because one of the people that I quote in the book is an infantry officer who gives a dramatic description at one point of a very small cavalry detachment when they were having trouble taking the German position. A small cavalry detachment charged up the hill, disappeared over the brow of the hill and then were never seen again.
So I thought could I find this hill? Well, I went looking for it. I found it. What you realize when you're there is that it's not something which I walking around or you walking around today would describe as a hill. It's, you can barely see the slope in the ground and then that makes me realize that all these descriptions you read from the war of capturing hilltops and ridges and crests and so on are written from the point of view of somebody who's lying on the ground trying to stay underneath all those bullets. Just it's a useful reminder when you go to the place
Did the soldiers really perceive those hills to be larger than they were? Their perspective from ground level could have made the relief stand out but there could be a couple of other things going on. Maybe relief was sharper during the war but in the decades after the war the landscape has been reworked intensely. Soil rearranged by farming, ditches and crevasses filled and the topography really has become mellower. There is also the soldier's psychological perception of the landscape around them. After watching their comrades being mown down in futile charges against German machine gun pickets, for those bone tired shell shocked soldiers the words hill, valley and crossing may have taken on a more threatening meaning. A gentle slope might seem steeper than it was, a shallow depression might appear in the mind's eye as a deep valley. When you need to cross them to reach the enemy territory they might appear to be desperately formidable obstacles.. as menacing and impassable as the enemy waiting for you in the trenches.