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@UML(identifier="CV_HexagonalGridCoverage", specification=ISO_19123) public interface HexagonalGridCoverage
Evaluates a coverage at direct positions within a network of hexagons centered on a set of grid
points. Evaluation is based on interpolation between the centres of the ValueHexagon
s
surrounding the input position.
Coverages are sometimes based on tessellations composed of regular hexagons. Such tessellations are usually called hexagonal grids. In fact, the centers of a set of regular hexagons that form such a tessellation correspond to the grid points of a quadrilateral grid. That grid can be described as a rectified grid in which the two offset vectors are of equal length but differ in direction by 60°. The length of a side of the hexagon is L = S×tan 30°, where S is the length of the offset vector. This means that the values in the coverage range can be stored as a grid values matrix and accessed through a sequence rule. The hexagons are the Thiessen polygons that are generated around the grid points.
NOTE: A set of Thiessen polygons generated from the grid points of any 2-dimensional rectified grid described by two offset vectors that are equal in length but not orthogonal will be a set of congruent hexagons. The hexagons will be irregular unless the offset vectors differ in direction by exactly 60°.
Method Summary | |
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Set |
evaluate(DirectPosition p,
Collection<String> list)
Returns a set of records of feature attribute values for the specified direct position. |
Set<ValueHexagon> |
getElements()
Returns the set of value objects used to evaluate the coverage. |
InterpolationMethod |
getInterpolationMethod()
Returns the interpolation method to be used in evaluating the coverage. |
GridValuesMatrix |
getSource()
Links this hexagonal coverage to the grid values matrix for which it is an evaluator. |
Set<ValueHexagon> |
locate(DirectPosition p)
Returns the set of values hexagon that include the domain objects containing the specified direct position. |
Methods inherited from interface ContinuousCoverage |
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evaluate, evaluateInverse, getInterpolationParameterTypes, select |
Methods inherited from interface Coverage |
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evaluate, evaluate, evaluate, evaluate, evaluate, evaluate, find, find, getCommonPointRule, getCoordinateReferenceSystem, getDimensionNames, getDomainElements, getDomainExtents, getEnvelope, getMetadataNames, getMetadataValue, getNumSampleDimensions, getRangeElements, getRangeType, getRenderableImage, getSampleDimension, getSources, list |
Method Detail |
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@UML(identifier="element", obligation=OPTIONAL, specification=ISO_19123) Set<ValueHexagon> getElements()
getElements
in interface ContinuousCoverage
@UML(identifier="interpolationType", obligation=OPTIONAL, specification=ISO_19123) InterpolationMethod getInterpolationMethod()
getInterpolationMethod
in interface ContinuousCoverage
@UML(identifier="locate", obligation=OPTIONAL, specification=ISO_19123) Set<ValueHexagon> locate(DirectPosition p)
locate
in interface ContinuousCoverage
@UML(identifier="evaluate", obligation=MANDATORY, specification=ISO_19123) Set evaluate(DirectPosition p, Collection<String> list)
@UML(identifier="source", obligation=MANDATORY, specification=ISO_19123) GridValuesMatrix getSource()
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