Hotspots are used to store exact positions of important points� during you survey. If there is an object or a point you wish to place exactly, or make a note of, within your floor plan, then hotspots are the tools for that. A hotspot acts like a corner in the wall. It can be surveyed to any other two points, and it also can be used as a reference point of a distance measure.
If there is a wall, in which the length cannot be measured as e.g. a bookshelf stands there, then using a hotspot (that directly sees both ends of the wall) the two endpoints of the wall can easily be measured. Then the hotspot should also be measured from other corners, and the partially hidden wall can be clearly measured.
To place a hotspot just tap the screen in the required position. Hotspots can be moved using the Move Corner� tool as it were a corner in a wall.