## Question:## How do you describe the leaf shapes of Aspen trees?- broadly ovate to suborbicular or oblate-orbicular --- Flora of the British Isles
- broadly ovate to orbicular --- New Britton and Brown illustrated Flora of the Northeastern United States and Adjacent Canada
- kidney-shaped, reniform or oblate --- Gray's Manual of Botany
- suborbicular --- New Flora of the British Isles
- almost round --- The Wild Flower Key: A Guide to Plant Identification in the Field
- ...
## How do you integrate them into a uniform description and use it afterwards?In order to integrate them into a formal ontology, or to check their compatibility, we need- an appropriate semantic model in which the semantics in such NL descriptions can be captured and the compatibility between descriptions can be measured;
- a formal language which is expressive enough to represent the NL semantics and also compatible with the current ontology system;
- a proper integration strategy for combining information from different sources.
## Shape ModellingThere are several general ways to model shapes:- Interpolation techniques and curve-fitting. For example, polygonal fitting (i.e. selecting points on the margin); simple interpolation using, say, polynomials, through to sophisticated curve-fitting techniques, e.g. using (elliptic) Fourier series, or using splines;
- Formulae for generating shapes, e.g. SuperFormula. Figure 2 gives some common leaf
shapes generated from the SuperFormula.
Figure 2. Common Leaf Shapes
Generated by the SuperFormula
Here, we derived a special leaf
shape model: Four-Feature Model
- Length/width ratio
- The position of the broadest part
- Apex angle
- Base angle
## Syntax of Shape Descriptions
## Semantics Construction
The semantics of complex descriptions is constructed by applying
certain operations on that of basic terms, including modifying
its length/width ratio to get "broadly" or "narrowly" shape, use an
intermedia shape for hyphenated shape "A-B" while a "super-shape"
representing a range for shape A to shape B, etc. |

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