Name
point
Synopsis
Content Model
<point> = EMPTY
Attributes
| Name | Type | Default |
|---|---|---|
| x | Decimal number: x value of an inflection point | Required |
| y | Decimal number: y value of an inflection point | Required |
Description
An element that describes the exact inflection points that make up curves in the ForestModel. Both x and y attributes are required in the point element. Interpolation techniques used by the model can be used to reduce the number of points required to describe curves. For example, Patchworks uses a straightline interpolation technique between points, and extrapolates first and last values beyond the defined range. This means that a curve will continue on in a straight line above the maximum x value and below the minimum.
Keeping this interpolation scheme in mind can greatly reduce the number of points required to produce the desired curve. For example, many area curves maintain a constant value through time. This relationship can be represented with a single point, allowing the interpolation methods to provide values for all of the domain.
<curve id="area">
<point x="0.0" y="1.0"/>
</curve>
Parents
These elements contain point: curve.
Children
The following elements can occur in point: NONE
Attributes
xThe x attribute represents the domain axis of the curve and is stored with floating point precision.
yThe y attribute represents the range axis of the curve and is stored with floating point precision.
See Also
Examples
In the following example a simple curve was defined using only three point elements to describe the disturbance of a stand. This simple curve conveys the idea that a stand will appear disturbed for the first 20.0 years, then at age 21 it no longer appears disturbed (21.0, 0.0 continued until end of planning horizon).
<attributes id="Seral">
<attribute label="%f.Seral.disturbed" cycle="false">
<curve>
<point x="0.0" y="1.0" />
<point x="20.0" y="1.0" />
<point x="21.0" y="0.0" />
</curve>
</attribute>
</attributes>
A more complex curve would require more inflection points like below.
<curve id="754.PWST.Prsnt.Sb">
<point x="5.0" y="0.0" />
<point x="35.0" y="0.0" />
<point x="45.0" y="1.0" />
<point x="55.0" y="1.0" />
<point x="75.0" y="3.0" />
<point x="85.0" y="3.0" />
<point x="105.0" y="5.0" />
<point x="165.0" y="5.0" />
<point x="175.0" y="4.0" />
<point x="195.0" y="4.0" />
<point x="205.0" y="3.0" />
<point x="225.0" y="3.0" />
<point x="235.0" y="2.0" />
</curve>