If you are browsing a topic or subject hierarchy of links in the Ashworth College Library andthen display a document from the results list, the trail of links you clicked to find that document<span>may be presented at the top of the document view. This trail is often called a content trail</span>
water pump pliers i think?
The GIS is the Geographic Information System which is used for map making and related to the GPS to get the locations of things which go on the map. One advantage of the GIS is that it can store many types of information for a point on the map and hovering over that point can give one a list of the different types of information available. For example, a drill hole collar ie a discrete point can have the co-ordinates of the hole collar, the diameter of the hole, the inclination of the hole, the azimuth of the hole, dip tests on the hole, and even the assays if necessary.