Anti-aliasing is a system whereby the edges of letters or lines use shades between the color of the type or line and the color of the background to 'smoothen' any curved line.
An aliased graph (which is the default setting) will look like the image below:
An anti-aliased graph will look like the image below:
This setting can be changed by the Graph > Preferences > Enable Curved Lines setting as shown below for Strategy Developer 9.x and newer:
