You need to be a member in order to leave a comment. I fetch the values from several different websites for comparison purposes see question 4.
A degree of longitude is widest at the equator with a distance of 69. You can go through all lines of Longitude just by turning around in a circle without going any distance.
Recommended Posts. That means I have to have code on my server that makes the actual request and, as explained above, that could lead to the underlying website blocking my server's IP address.
Share this post Link to post. Reverse geocoding is just the opposite -- obtaining the address corresponding to a specified latitude and longitude.
This system starts with an imaginary grid of lines that cover the entire planet; locations are measured based on both X and Y coordinates within the grid.
Unlike latitude, the distance between degrees of longitude varies greatly depending upon your location on the planet. The earth is approximately 24,000 miles in circumference, which means it is 12,000 miles from the North Pole to the South Pole.
Longitude At Other Latitudes: However, the earth is slightly elliptical in shape and that creates a small variation between the degrees as we work our way from the equator to the north and south poles.
Calculating the Distance between two points on the Earth To calculate the distance between two points of Latitude and Longitude on the Earth's surface, See one of the following: How far is a second on the GPS? One minute of latitude equals one nautical mile and degrees of latitude are 60 nm apart. This is the level of accuracy used in this course.
The metric system is not normally used in the nautical world except, increasingly, for use in charted depths and elevations. Sometimes one or more of the websites happen to be down at the time the request is made.
In order to precisely locate any spot in the world, therefore, we use a geographic coordinate system that is measured in degrees of latitude and longitude. Now let me explain why I don't have a batch reverse geocoder.
Degrees of latitude are always 60 nautical miles apart. For most calculations, 6,000 feet is close enough. One second equals about 16.
You can go through all lines of Longitude just by turning around in a circle without going any distance. You could use what is known as a 'haversine' formula to calculate the distance, but unless you are a whiz at trigonometry, it is not easy. In Google Maps, for example, you can simply click on a location and a pop-up window will give latitude and longitude data to a millionth of a degree. Just to be clear: That's because of the way the different websites behave when they don't recognize the address.