03 Oct 2024
“Geodetic coordinates” is another term used to refer to the same system of latitude and longitude.
This term is commonly used in geodesy, the science of measuring Earth’s shape, orientation, and gravity field.
You could also refer to it more broadly as a “coordinate system” or “spatial reference system,” especially when including other systems like UTM (Universal Transverse Mercator) or MGRS (Military Grid Reference System).
In summary, terms like:
- Geographic coordinates
- Geodetic coordinates
- Coordinate system
- Spatial reference system
all relate to the concept of positioning on Earth.
Breakdown
Geographical coordinates are a system used to pinpoint locations on Earth's surface. They consist of two numbers: latitude and longitude.
Latitude
- Measures how far north or south a location is from the Equator.
- Values range from 0° at the Equator to 90° North (North Pole) or 90° South (South Pole).
- Positive values are for locations north of the Equator, and negative values for locations south.
Longitude
- Measures how far east or west a location is from the Prime Meridian (which passes through Greenwich, England).
- Values range from 0° at the Prime Meridian to 180° East or 180° West.
- Positive values are for locations east of the Prime Meridian, and negative values for locations west.
Example Coordinates (Decimal Format)
- New York: 40.7128° N, 74.0060° W
- Sydney: 33.8688° S, 151.2093° E
Each coordinate pair uniquely identifies a position on Earth.
Degrees, Minutes, and Seconds Format
Sometimes, geographical coordinates are represented using degrees (°), minutes (′), and seconds (″), which provide more precision.
Example
Coordinates: 48°24′37″N 11°28′15″E
Breaking it down:
1. Degrees (°): The largest unit, ranging from 0 to 90 for latitude and 0 to 180 for longitude.
2. Minutes (′): There are 60 minutes in one degree. So, 1′ is 1/60th of a degree.
3. Seconds (″): There are 60 seconds in one minute, or 1/3600th of a degree.
In this case:
- Latitude: 48 degrees, 24 minutes, 37 seconds North
- Longitude: 11 degrees, 28 minutes, 15 seconds East
Conversion to Decimal Degrees
To convert from degrees, minutes, and seconds to decimal degrees, use this formula:
- ( \text{Decimal Degrees} = \text{Degrees} + \frac{\text{Minutes}}{60} + \frac{\text{Seconds}}{3600} )
For the example 48°24′37″N 11°28′15″E:
- Latitude: ( 48 + \frac{24}{60} + \frac{37}{3600} = 48.4103° N )
- Longitude: ( 11 + \frac{28}{60} + \frac{15}{3600} = 11.4708° E )
Thus, the coordinates in decimal format are:
- Latitude:
48.4103° N - Longitude:
11.4708° E