RockWare offices will be closed Thursday January 1 for New Year’s Day – orders will ship the following day. We will be open for business on Wednesday December 31. Happy New Year from RockWare. You can create vector maps from information in one grid or two separate grids. The two components of the vector map, direction and magnitude, are automatically generated from a single grid by computing the gradient of the represented surface. At any given grid node, the direction of the arrow points in the direction of the steepest descent. The magnitude of the arrow changes depending on the steepness of the descent. Two-grid vector maps use two separate grid files to determine the vector direction and magnitude. The grids can contain Cartesian or polar data. With Cartesian data, one grid consists of X component data and the other grid consists of Y component data. With polar data, one grid consists of angle information and the other grid contains length information. Overlay vector maps on contour or wireframe maps to enhance the presentation! A vector map of Mt. St. Helens overlaid on a contour map. Use a color scale bar or legend to indicate the magnitude of the arrows. Source.