Gaussian beamlet decomposition (GBD) and Gaussian beamlet propagation (GBP) have become accepted and well know methods for physical optics modeling, implemented in many commercial optical simulation software packages. Typical applications are the modeling of diffraction problems, involving collimated or low-divergence laser beams. For these applications and many more typical textbook examples, it can be shown that GBP and GBD offer an excellent match between experimental data and modeling results. For highly astigmatic laser beams, on the other hand, no published examples can be found, where GBP and GBD were used to model the resulting irradiance distribution and compared it to experimental data. A typical representative of such a system is a line laser system, which can be found in a variety of applications. Line lasers are used e.g. as pattern generators in triangulation-based 3D measuring systems, as light curtains in machine safety applications or for shape and volume measurements in logistics automation. Already in a very early product development phase, the knowledge of the irradiance distribution is crucial to ensure product functionality and product safety. Therefore, the measured irradiance data of a typical line laser system are compared here with the modeling results of a simulation software supporting the GBD and GBP methods. Under most conditions, there is a good agreement found between the measurement and simulation data, which suggests that GBD and GBP are useful tools in the design process of line laser systems.