DEM

Source- http://en.wikipedia.org/wiki/Digital_elevation_model

DEM or digital elevation models are used most often for remote sensing. This kind of models show topographic information especially elevation. It gives us a great understanding of how land around changes through hills, mountains..etc. This map above is a relief map of Sierra Nevada. As you can tell from this map DEM sometimes use different colors to indicate where the highest peaks are and the lowest come from. Green to yellow is usually the lowest, while orange, red and even some white are the highest receptively.  The patterns of this particular map is there seems to be a mountainous where the orange-red is, some major peaks in the middle of it.