The Wind Resource Grid was first introduced by the Risø National Laboratory (since 2008, the Technical University of Denmark, DTU). WRG files are the outputs of the Wind Atlas Analysis and Application Program (WAsP by DTU) and nowadays are also produced by Vortex and other companies. Several tools can read and import WRG files like OpenWind, WindFarmer, and WindPro.
The Wind Resource Grid file is an ASCII (text) file. The first line contains the coordinates, height above ground level, the number of grid points (X and Y), and the cell size. Then contains the wind rose and sector-wise wind speed distributions for each node in the grid. The detailed format of each line is shown in the table below.