Final answer:
Map overlays require reference points such as the map's scale in kilometers and miles, an arrow pointing north, and the explanation of symbols used for accurate positioning. The scale helps match the overlay with the map beneath, while latitude and longitude coordinates are essential for identifying precise locations and understanding celestial navigation.
Step-by-step explanation:
When using map overlay, reference points are used to show exactly where the overlay fits on the map. These reference points include elements such as:
- The scale of the map, which denotes the ratio of distance on the map to the actual distance on the ground. Maps typically express scale in both kilometers and miles and include a visual scale bar for relative distance.
- An arrow indicating north to determine orientation, along with the map's latitude and longitude for precise location identification on the Earth's grid.
- An explanation of symbols, colors, lines, or icons used on the map, assisting the user in interpreting various features depicted on the map.
These tools enable the user to align the overlay with the map beneath accurately, ensuring that all major features like cities or natural landmarks match correctly. Additionally, understanding latitude and longitude is crucial for identifying the apparent motion of celestial objects when creating astronomical maps, providing a connection between earthbound and celestial navigation.