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Geocaching resources

History of GPS

GPS consists of a series of satellites, called NAVSTAR (navigation satellite timing and ranging) and a ground based GPS receiver. The NAVSTAR satellites orbit the Earth at a distance of approximately 19 000 kilometres and take 12 hours to complete an orbit of the Earth. The GPS receiver determines its location on the Earth's surface by collecting signals from the orbiting GPS satellites.

Read more: History of GPS

Maps for your Garmin GPS


There are many commercial mapping products on the market, but did you know that there are also a number of free, and legal, maps available for you to download?

This tutorial will take you through a few of the options available, how to upload them to your Garmin GPS and you can make them better.

For most maps you will need:

  • A Windows PC or Mac
  • At least 500 MB of free hard drive space
  • A licensed copy of Garmin Trip and Waypoint Manager, MapSource or CityNavigator (PC), or Garmin RoadTrip and Garmin MapInstall (Mac).

Read more: Maps for your Garmin GPS

Geocaching and the police

nswpolice 300x200From time to time, geocachers ask how they should conduct themselves with Police and security personnel. Additionally, Police would like geocachers to understand how they can minimise unnecessary, and often costly, Police involvement.

This article results from discussions with NSW Police, including some involved in "suspicious package" callouts.

Firstly, it is important to remember that police must attend to concerned calls from the public, particularly in this era of heightened alertness. You can reduce the chances of having to explain yourself by considering these guidelines.

Read more: Geocaching and the police

Geocaching with Garmin Colorado and Oregon

oregon gpsrThe Garmin Colorado and Oregan GPS receivers have been built with geocaching in mind. Their ability to play Wherigo caches and handle GPX files make it a logical unit for geocachers.

But there are a few things to keep in mind when tranferring GPX files into the unit.

When  you connect the GPS receiver to your computer, it should appear as a mountable drive - similar to an external hard or flash memory drive. Double click on the drive to open it and look for the GPX folder - not the Geocache folder. Drag GPX file containing geocaches, typically a pocket query from Groundspeak or Geocaching Australia, into this folder. Eject or unmount the drive from the computer and restart the unit.

If the geocaches in the GPX do not appear, check that you did not copy across a zip file. A Groundspeak pocket query, by default, are zipped. You must unzip these before copying them across.


Read more: Geocaching with Garmin Colorado and Oregon

Degree and minutes

Many years ago, cartographers (map makers) knew that the world was a sphere. To help people figure out where they were located on this sphere, they devised a grid system called longitude and latitude.

The Earth rotates once every 24 hours around its axis. The points where this axis meets the surface are called the North and South Poles. Half way between the North and South Pole is an imaginary line that runs around the Earth called the equator.

Read more: Degree and minutes