Modality in Gerber Data

Often in Gerber data, movement from one X/Y coordinate pair point to another will require only one of either the X or the Y value to change. As well, it is also likely that if the plotter is writing a line with multiple segments that the light will stay on from segment to segment as it draws the line.

Both of these instances will therefore use redundant commands, which will unnecessarily increase the size of the data file.

RS-274D format allows redundancy to be omitted. The following table shows the results of the removal of the redundancy in drawing a box with four corners.

Even from this small example, the amount of data is greatly reduced, thereby reducing the final data file size.