The lines on the map - azimuth lines - indicate the direction from the red map pin towards specific events, such as sunrise or moonset, or to the sun or moon at the selected time. The lines are color-coded: orange means sun, blue means moon.
Here's a labelled screenshot showing all the common azimuth lines:
Interpreting the lines
There are two ways to think about the lines:
- If you stand at the red pin, the line indicates the direction you need to look in, relative to true north, to view the indicated event or body (sun/moon)
- If you are a photographing a subject situated at the red pin, the lines indicate the direction from which light will hit your subject
While adjusting the time of day
Additional lines are shown as you adjust the time of day using the time slider. These include both projection lines and relative shadow lengths:
Projection lines can used to help align your shots. For example, if you were to walk away from your subject situated the red pin, but wanted to keep the sun directly aligned directly behind it, you should walk in the direction shown by the projection line.
Relative shadow length lines show the relative length of shadows for the selected time of day. A longer line means longer shadows. You'll notice as you approach sunset, the shadows get longer, as you'd expect. You'll only see shadows from the moon when the sun is down and the moon phase is not near new.
You may want to check out this short video explaining the 6-degree Shadow Circle also.