Special tree and deadwood GIS entities
In addition to the mapped data which can be categorized into the general types of map layers (point, line, polygon); the user can take the advantage of specially designed Field-Map forestry layers: Tree, Deadwood, and Transect.
The Tree layer. It consists of center points and polygons circumscribing tree stem at breast height (basal area of the tree). It has a number of predefined system attributes such as DBH, height, crown base, etc.
The Deadwood layer. Each piece of deadwood is represented by a line leading lengthwise through an axis and connecting all vertices (base, all break points and end) of the deadwood and by a polygon circumscribing the deadwood in a horizontal projection. The polygon is created by connecting the base and the top (or optionally at each break point) of the deadwood.
Deadwood can e defined by two end points (mostly conifers) and additionally by a number of break points (broadleaf trees).
The length and volume of each deadwood is calculated automatically. Field-Map also stores information about the Z co-ordinates of break points, so the volume is always calculated in 3D projection (this is particularly important on the slope, where “2D volume” in underestimating)