Name

point — provides inflection points of a curve

Synopsis

Content Model


	    <point> = EMPTY

	    

Attributes

NameTypeDefault
xDecimal number: x value of an inflection point Required
y Decimal number: y value of an inflection pointRequired

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

x

The x attribute represents the domain axis of the curve and is stored with floating point precision.

y

The y attribute represents the range axis of the curve and is stored with floating point precision.

See Also

curve

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>