How to Use: Distance Signpost

The Distance Signpost shows the air distance, also known as the great circle distance, between a location and cities around it.

How to Use the Distance Signpost

  • Go to the Distance Signpost set-up page and enter or select a location.
  • The selected location is in the center of the graph; the blue arrows point to locations around it, indicating their heading, as you would see on a compass.
  • Use the zoom buttons or the slider at the bottom of the graph to change the scale of the display; the slider appears when you hover over it. The distance represented by the gray circles changes depending on the level of zoom. It is indicated in red in the bottom-right corner.
  • Hover over an arrow to see the exact heading.
  • Click on an arrow to see the shortest route between the two locations on a world map in the Distance Calculator.
  • Click on the small map below the Distance Signpost to see the selected location on the Time Zone Map.
  • To select a different location, use the search field below the signpost or click on a location in the table at the bottom.

FAQ: Troubleshooting

Why can't I choose which locations are displayed?

While it is not possible to pick and choose every single location displayed in the Distance Signpost, it is possible to change the scale of the graph, showing either cities close by or far away. You can change the scale by using the zoom buttons or the slider that appears at the bottom of the graph when you hover over it.

Why does it show the wrong distance?

If you believe that the calculator shows the wrong distance, please consider the following before sending us your error report:

  • The Distance Signpost shows the air distance or great circle distance. It does not show road distances.
  • Planes often don't take the shortest route between two locations, so a flight route may be considerably longer.

If you still think the calculator shows the wrong distance, please let us know.

Why is the distance shown in km / mi / nm / ft?

The distance unit can be changed under Distance/Visibility in the Settings Menu.

The time has the wrong format. How do I change between the 24-hour and AM/PM clock?

Our system supports both 24-hour and 12-hour (am/pm) clock formats. To change the format, please go to My Units and make a selection in the Time Format drop-down, and click Save Settings.

Why does the graph show a different direction than my map?

The Distance Signpost shows the great circle or air distance between any two locations, which is the shortest distance as measured by drawing a path along the Earth's surface. Because the Earth is a sphere, it is not possible to show its surface on a map without distorting it.

This means that a straight line along the Earth's curved surface in most cases appears as a curved line on a map—and that the heading of the shortest route normally does not match the heading of a straight line on a 2-dimensional map.

Why do planes take longer routes?

Planes often do not follow the shortest route between two locations. Reasons can include weather conditions, security considerations, or available infrastructure.

What's more, the calculator shows distances at sea level. Since planes fly at a considerable altitude, they have to travel a longer distance to get from point A to point B. For example, the distance increases by about 0.2% for a plane flying at an altitude of 40,000 feet, even if it follows the shortest possible route.

Why isn't my town included?

This service includes all 5000+ locations in our database. Some of our services also include millions of additional locations provided by the GeoNames database. However, these GeoNames locations cannot be selected in this service yet.

FAQ: General Info & Instructions

Does the signpost show road distances?

No. It shows the air distance between the location you pick and other locations worldwide.

What is the great circle distance or air distance?

The air or great circle distance is the shortest distance between any two locations on Earth as measured by drawing a path along the Earth's surface at sea level.

What does “Locations around this latitude/longitude” mean?

The lists on the right side show locations that approximately share the same latitude or longitude as the selected location. Latitudes and longitudes are explained here.

What does “Locations farthest away from...” mean?

The list on the right side shows the locations that are farthest away from the selected location. In other words, you would roughly end up there if you dug from the selected location straight down and through the Earth's core.

How do longitudes and latitudes work?

They are explained here.

What do the abbreviations and arrows in the table mean?

They show the direction you would have to travel in to get from the selected location to the location shown in the table row.

  • N = North
  • E = East
  • S = South
  • W = West

The headings are stated in degrees, with 360 in a full circle, counted in a clockwise direction from north. As shown on a compass, north is 0 degrees, east is 90 degrees, south is 180 degrees, and west is 270 degrees. All headings are based on true north.

Are the headings based on true north or magnetic north?

All headings are based on true north.

Do the gray circles on the Graph denote latitudes?

No. They provide an indication of the signpost's scale, which can be changed by using the zoom buttons or the slider that appears at the bottom of the graph when you hover over it. The red number in the bottom-right corner indicates the distance represented by the spacing between the circles.

Would I get to the city by following the displayed heading?

Depends. If you started your journey by traveling into the direction displayed in the graph and then kept going straight, you would reach the location. However, if you looked at your compass during your journey and followed the same heading consistently, you would not reach you destination, especially if it's far away.

The reason is Earth's curvature. Because the Earth is a sphere, the compass heading changes underway. For example, if the shortest route between two locations goes via the North Pole, the initial heading is north, but as you cross the pole, it changes by 180° from north to south. If you simply kept going north, you'd be stuck at the North Pole.

How does your algorithm work? Can you help me program my own?

We are a small team with a very extensive website to manage, so unfortunately, we do not have the capacity to share detailed information about our algorithms or provide programming help.

Where can I find more information about the site and its services?

The General FAQ Page answers your questions about timanddate.com, our services, site-wide settings and customization options, as well as advertising and copyright policies.

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