Displaying elevation information from a digital map

A non-transitory computer-readable medium which stores a set of instructions which, when executed by a processor, configures the processor to perform a method of rendering a display image generated from digital map information, the method comprising:

• determining elevation information from the digital map information;
• determining display scale information for the display image;
• determining a shading value to apply to each pixel in the display image, the shading value being based on a first shading function and a second shading function and varying as a function of the elevation information and the display scale information;
• applying the shading value to the respective pixel in the display image, to generate a display that represents elevation information by pixel shading that varies with display scale;
• and
• rendering a map image from the digital map information using the determined shading value associated with each pixel.

Apparatus for rendering a display image generated from digital map information comprising:

• a memory storage for storing the digital map information;
• one or more processors coupled to the memory storage, wherein the one or more processors are operative to;
• determine elevation information from the digital map information;
• determine display scale information for the display image;
• determine a shading value to apply to a pixel in the display image, the shading value being based on a first shading function and a second shading function and varying as a function of the elevation information and the display scale information;
• and
• apply the shading value to the respective pixel in the display image, to generate a display that represents elevation information by pixel shading that varies with display scale.