There are 5 different modes in Field-Map for measuring tree height:
- Height measurement “Distance using Position” mode. This mode is very effective on plots where conditions allow you to see and measure several trees from one place. First the user needs to have all the tree positions. After taking its current position, the user can measure the attributes of all the visible trees without measuring the distance to them.
- Height measurement “Distance + Base using Position” mode. This mode is particularly useful in dense forests with tall trees (tropical forests) where it is necessary to move faraway from the tree in order to see its top. By using positioning and navigation it is possible to move away from the tree and stay georeferenced.
- Height measurement “Distance Measurement” mode. This mode is useful in plots with high stem density where the user cannot see more than one tree from your position. With this mode the user do not have to worry about its or the trees position before the user starts measuring heights, because the laser is used as a classic hypsometer.
- Height measurement “Distance+Base using Main Pole”. This mode is similar to the previous mode (“Distance Measurement”), but this time Field-Map calculates the inclination to the stem base automatically. When the user measure the distance to the tree, it is required that the reflector is at the correct height (Height of reflector = Main Pole Length).
- Height measurement “Direct height Measurement” mode. This mode uses built-in height measurement function of the laser rangefinder. Field-Map expects height (not inclination) data from the laser.