====== Changing the vertical range ======

You may find that after generating your heightfield that it's too steep or flat, should be moved up or down, or perhaps the sea coverage should be changed. The //change heightfield vertical range// window (below) allows you to do all this, and is accessed from the '//Operations->Heightfield->Change vertical range//' option in the menu.

{{ l3dt:userguide:dialogs:hf_v_rescale.png }}

The controls are as follows:

===== Min. Alt. and Max. Alt. =====

The height, in metres, of the lowest and highest point in the heightfield. Changing these values will shift and re-scale all values in the heightfield to fit between these values. 

<note tip>
To invert the heightfield, switch the minimum and maximum altitudes (ie. make //min// > //max//).
</note>

===== Average altitude =====

The average height of all points in the heightfield, in metres. Changing this value will //shift// all the terrain up or down, without changing the altitude range. Hence, the steepness will be unaffected. 

===== Altitude range =====

The difference between the maximum altitude (//max. alt.//) and the minimum altitude (//min. alt.//) within the heightfield, in metres. Changing this value will leave the average altitude unaffected, but will increase or decrease the distance between the minimum and maximum values. A smaller range value will produce flatter terrain, whilst a larger range value will produce steeper terrain. 

===== % above sea-level =====

The percentage of area in the heightfield that is above sea-level (defined to be 0 metres). Changing this value will shift all values up or down, without changing the altitude range.