A garden sundial is a simple way to illustrate how to use the Sun to tell time. You can make them with simple equipment or construct quite elaborate versions. The only information needed to build a garden sundial is the latitude and longitude of the station and the width of the plot of land you wil be using. The height of the sundial should be about the height of the pointer (about 4 ft.)
Below is a form to enter a geographic location and width, which will be used to calculate the important points for a garden sundial. The important points are the height of the ellipse, locations of the foci of the ellipse (or drawing the ellipse), the distances of the hour centers from the origin, and the location of the pointer from the origin.