This file should take in any '.alog' file and automatically create the matlab structures from the given device, message, and data values in the file. If a string of data is provided, say from a lidar, you will get a data structure that includes cells. The way to acces your data, say the first set of angle data and plot it would be done with: plot(gIbeoAlascaXT.zAngleAlpha{1}) Note: it is using {} and not ().