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The main part of the application window can be scaled/zoomed using the mouse wheel or by clicking the magnifying class glass icons. Clicking with the left mouse/touchpad button and dragging over the raw radar data allows the view to be panned.
The image displayed presents the intensity of radar energy reflected from each point within the radar’s field of view by the image brightness at the corresponding location.
This page has described the simplest use of the software SPxRadarView-Lite. In the zip file downloaded, there is a PDF instruction manual, and further information is presented here.