This program creates charts showing the direction and length of a shadow cast by the top of a pole (gnomon) of a given height upon a rectangular area, typically a roof or a field. The shadow cast by a pole can be drawn on the diagram by connecting a line from the pole's location (0, 0) to the end of the shadow at the time of interest. Shading of a PV array, by a pole or object causing the shading, can be seen by drawing the location of the array on the diagram relative to the pole. By default, dates are spaced about 30 days apart from one solstice to the next. The width and length of the plotted area can be specified and there are a several options available to allow you to alter the chart's appearance.
Resulting charts are displayed in your Web browser window, and they are formatted for printing. Two file formats are currently available: PDF (Adobe), and PNG, an international standard.
Please note that some charts, especially those for Arctic or Antarctic latitudes and those where the gnomon height is very short in relation to the dimensions of the chart, may have labels crowded together or otherwise display unexpected properties. Be sure to experiment with various sizing and display options.
© 2010, UO Solar Radiation Monitoring Laboratory.
Last revised: April 9, 2010.
Home page URL: solardat.uoregon.edu