Check this option to automatically stretch the color scheme's minimum and maximum data values to match the full range of values across all pixels within the current map view. This sets the lower and upper bounds for the category's legend and optimizes the use of colors each time the map zoom changes. Turn this feature off when you prefer to apply a set color scheme globally. Because it requires computation at each zoom change, you may also prefer to turn this feature off for faster map generation. You can always press "compute" below to optimize the colors as desired.