Difference between revisions of "Coordinates"

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[[Coordinates]] are a means of numerical description for a location on the earths' surface. [[Geocaching]] uses coordinates of [[Latitude and longitude | Latitude]] and [[Latitude and longitude | Longitude]] (Lat/Lon) to describe the location of the cache or its' intermediate [[waypoint]]s.
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[[Image:Coordinates.jpg|thumb|right|300px|A set of coordinates]]
  
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For the purposes of geocaching, Lat/Lon coordinates are expressed in Degrees, Minutes, decimal minutes ( DDD°MM.mmm' ), but for purposes of general navigation (especially at sea) Lat/Lon is expressed in Degrees, Minutes and Seconds ( DDD°MM'SS" ).
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[[Coordinates]] are a set of numbers, [[Latitude]] and [[Longitude]], used to define a location, or [[waypoint]].
  
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An alternate system of coordinates is [[UTM]], which is short for [http://www.uwgb.edu/dutchs/FieldMethods/UTMSystem.htm Universal Transverse Mercator]. UTM would be a better system to use for geocaching, because it's more accurate. Being based on the metric system it's well suited to terrestial applications, unlike DDD°MM.mmm'. However, that point seems to have been overlooked at the time geocaching was invented, so we are stuck with DDD°MM.mmm', unless you want to convert from DDD°MM.mmm' to UTM and back again.
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==Format==
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There are four commonly used formats for [[coordinates]]:
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* DDD° MM.mmm' - Degrees and decimal minutes - used in [[geocaching]]
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* DDD° MM'SS" - Degrees, minutes and seconds - used in general naviation, particularly nautical navigation
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* +/-DDD.dddd° - Decimal degrees, with North and East being positive, S and W negative.
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* UTM - [http://www.uwgb.edu/dutchs/FieldMethods/UTMSystem.htm Universal Transverse Mercator] - UTM would be a better system to use for geocaching, because it's more accurate and, being based on the metric system, it's better suited to terrestial applications. However, even though [[geocaching.com]] lists UTM as well as [[Latitude and longitude|Lat/Lon]], very few cachers or [[waypoint_management_software|waypoint management programs]] seem to use it.
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==Datum==
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[[Coordinates]] are based on a [[datum]].
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Geocache listings use the [[WGS84]] datum, and your [[GPS]] needs to be set to this.

Latest revision as of 22:38, 24 June 2007

A set of coordinates

Coordinates are a set of numbers, Latitude and Longitude, used to define a location, or waypoint.

Format

There are four commonly used formats for coordinates:

  • DDD° MM.mmm' - Degrees and decimal minutes - used in geocaching
  • DDD° MM'SS" - Degrees, minutes and seconds - used in general naviation, particularly nautical navigation
  • +/-DDD.dddd° - Decimal degrees, with North and East being positive, S and W negative.
  • UTM - Universal Transverse Mercator - UTM would be a better system to use for geocaching, because it's more accurate and, being based on the metric system, it's better suited to terrestial applications. However, even though geocaching.com lists UTM as well as Lat/Lon, very few cachers or waypoint management programs seem to use it.

Datum

Coordinates are based on a datum. Geocache listings use the WGS84 datum, and your GPS needs to be set to this.

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