Class ContourLineDetection

Index

Constructors

Properties

dataGrid debugMode rawLinearPathSegments CLOSE_GAP_TYPE_ABOVE CLOSE_GAP_TYPE_BELOW CLOSE_GAP_TYPE_NONE

Methods

areBothValuesOnRequiredPlaneSide detectAboveBelowLerpSegment detectContourPaths findHeight4FaceIntersectionLine findHeightFaceIntersectionLines findHeighteFace3IntersectionLine getLerpRatio isBetween lerp

Constructors

constructor

new ContourLineDetection(dataGrid, debugMode?): ContourLineDetection
Creates a new instance for calculating contour lines from the given data grid.
Parameters
- dataGrid: IDataGrid2d<number>
  The data grid to use. Must not contain any NaN or null values.
- Optional debugMode: boolean
  (optional) Pass true to log warnings on (rare) critical edge cases where the algorithm might fail.
Returns ContourLineDetection
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:43

Properties

`Private` dataGrid

dataGrid: any

debugMode

debugMode: boolean = false

`Private` rawLinearPathSegments

rawLinearPathSegments: Line[] = []

`Static` CLOSE_GAP_TYPE_ABOVE

CLOSE_GAP_TYPE_ABOVE: number = 1

`Static` CLOSE_GAP_TYPE_BELOW

CLOSE_GAP_TYPE_BELOW: number = 2

`Static` CLOSE_GAP_TYPE_NONE

CLOSE_GAP_TYPE_NONE: number = 0

Methods

`Private` areBothValuesOnRequiredPlaneSide

areBothValuesOnRequiredPlaneSide(valueA, valueB, criticalValue, closeGapType): boolean
Checks if both value are on the same side of the critical value (above or below). The closeGapType indictes if CLOSE_GAP_TYPE_BELOW or CLOSE_GAP_TYPE_ABOVE should be used as a rule.
Parameters
- valueA: number
- valueB: number
- criticalValue: number
- closeGapType: number
Returns boolean
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:433

detectAboveBelowLerpSegment

detectAboveBelowLerpSegment(x, y, nextX, nextY, criticalHeightValue, closeGapType): void
This procedure will look at the face4 at the ((x,y),(nextX,nextY)) position – which are four values – and determines the local contour lines for these cases.

This is used to detect and calculate edge cases on the borders of the underliying height data:
- left and right border (x=0, x=data.xSegmentCount)
- top and bottom border (x=y, x=data.ySegmentCount)
Resulting path segments will be stored in the global rawLinearPathSegments array for further processing.
Parameters
- x: number
- y: number
- nextX: number
- nextY: number
- criticalHeightValue: number
- closeGapType: number
  CLOSE_GAP_TYPE_ABOVE or CLOSE_GAP_TYPE_BELOW.
Returns void
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:375

detectContourPaths

detectContourPaths(criticalHeightValue, options?): GenericPath[]
Detect contour paths from the underlying data source.
Parameters
- criticalHeightValue: number
  The height value. If above data's maximum or below data's minimum then the result will be empty (no intersections).
- Optional options: {
      closeGapType: number;
      onRawSegmentsDetected?: ((rawSegmentsDoNotModifiy) => void);
      pathDetectEpsilon?: number;
      pointEliminationEpsilon?: number;
      useTriangles?: boolean;
  }
  - closeGapType: number
    CLOSE_GAP_TYPE_NONE or CLOSE_GAP_TYPE_ABOVE or CLOSE_GAP_TYPE_BELOW.
  - Optional onRawSegmentsDetected?: ((rawSegmentsDoNotModifiy) => void)
    - (rawSegmentsDoNotModifiy): void
      Parameters
      rawSegmentsDoNotModifiy: Line[]
      Returns void
  - Optional pathDetectEpsilon?: number
    (optional) The epsilon to tell if two points are located 'in the same place'. Used for connected path detection. If not specified the value 0.0000001 is used.
  - Optional pointEliminationEpsilon?: number
    (optional) The epsilon for duplicate point elimination (default is 0.000001).
  - Optional useTriangles?: boolean
    If set to true the detection will split each face3 quad into two triangle faces.
Returns GenericPath[]
- A list of connected paths that resemble the contour lines of the data/terrain at the given height value.
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:59

`Private` findHeight4FaceIntersectionLine

findHeight4FaceIntersectionLine(xIndex, yIndex, heightFace, heightValue, pointEliminationEpsilon): Line
This function will calculate a single intersecion line of the given face4 data segment. If the given face does not intersect with the plane at the given heightValue then no segments will be stored.
Parameters
- xIndex: number
  The x position (index) of the data face.
- yIndex: number
  The y position (index) of the data face.
- heightFace: DataGridFace4<number>
  The data sample that composes the face4 as a two-dimensional number array.
- heightValue: number
  The height value of the intersection plane to check for.
- pointEliminationEpsilon: number
Returns Line
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:155

`Private` findHeightFaceIntersectionLines

findHeightFaceIntersectionLines(xIndex, yIndex, heightFace, criticalHeightValue, pointEliminationEpsilon, useTriangles?): void
This function will calculate a single intersecion line of the given face4 data segment. If the given face does not intersect with the plane at the given heightValue then no segments will be stored.
Parameters
- xIndex: number
  The x position (index) of the data face.
- yIndex: number
  The y position (index) of the data face.
- heightFace: DataGridFace4<number>
  The data sample that composes the face4 as a two-dimensional number array.
- criticalHeightValue: number
- pointEliminationEpsilon: number
- Optional useTriangles: boolean
Returns void
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:228

`Private` findHeighteFace3IntersectionLine

findHeighteFace3IntersectionLine(xIndexA, yIndexA, xIndexB, yIndexB, xIndexC, yIndexC, heightFace, heightValue, pointEliminationEpsilon): Line
This function will calculate a single intersecion line of the given face3 data segment. If the given face does not intersect with the plane at the given heightValue then no segments will be stored.
Parameters
- xIndexA: number
  The x position (index) of the first triangle data point.
- yIndexA: number
  The y position (index) of the first triangle data point.
- xIndexB: number
- yIndexB: number
- xIndexC: number
- yIndexC: number
- heightFace: DataGridFace3<number>
  The data sample that composes the face4 as a two-dimensional number array.
- heightValue: number
  The height value of the intersection plane to check for.
- pointEliminationEpsilon: number
Returns Line
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:294

`Private` getLerpRatio

getLerpRatio(valA, valB, curValue): number
Get a 'lerp' value - which is some sort of percentage/ratio for the curValue inside the range of the given interval [valA ... valB].

Examples:
- getLerpRatio(0,100,50) === 0.5
- getLerpRatio(50,100,75) === 0.5
- getLerpRatio(0,100,0) === 0.0
- getLerpRatio(0,100,100) === 1.0
- getLerpRatio(0,100,-50) === -0.5
Parameters
- valA: number
- valB: number
- curValue: number
Returns number
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:470

`Private` isBetween

isBetween(valA, valB, curValue): boolean
Test if a given numeric value (curValue) is between the given values valA and valB. Value A and B don't need to be in ascending order, so valA <= curValue <= valB and valB <= curvalue <= valA will do the job.
Parameters
- valA: number
  The first of the two bounds.
- valB: number
  The second of the two bounds.
- curValue: number
  The value to check if it is between (or equal) to the given bounds.
Returns boolean
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:450

`Private` lerp

lerp(min, max, ratio): number
Helper function to lerp a numeric value.
Parameters
- min: number
  The min (start) value. Doesn't necesarily need to be the smaller one.
- max: number
  The max (end) value. Doesn't necesarily need to be the larger one.
- ratio: number
  The lerp ratio; usually a value between 0.0 and 1.0, but other values a valid for linear interpolation, too.
Returns number
- Defined in src/ts/utils/algorithms/ContourLineDetection.ts:482

Class ContourLineDetection

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

Returns ContourLineDetection

Properties

Private dataGrid

debugMode

Private rawLinearPathSegments

Static CLOSE_GAP_TYPE_ABOVE

Static CLOSE_GAP_TYPE_BELOW

Static CLOSE_GAP_TYPE_NONE

Methods

Private areBothValuesOnRequiredPlaneSide

Parameters

Returns boolean

detectAboveBelowLerpSegment

Parameters

Returns void

detectContourPaths

Parameters

closeGapType: number

Optional onRawSegmentsDetected?: ((rawSegmentsDoNotModifiy) => void)

Parameters

Returns void

Optional pathDetectEpsilon?: number

Optional pointEliminationEpsilon?: number

Optional useTriangles?: boolean

Returns GenericPath[]

Private findHeight4FaceIntersectionLine

Parameters

Returns Line

Private findHeightFaceIntersectionLines

Parameters

Returns void

Private findHeighteFace3IntersectionLine

Parameters

Returns Line

Private getLerpRatio

Parameters

Returns number

Private isBetween

Parameters

Returns boolean

Private lerp

Parameters

Returns number

Settings

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On This Page

`Private` dataGrid

`Private` rawLinearPathSegments

`Static` CLOSE_GAP_TYPE_ABOVE

`Static` CLOSE_GAP_TYPE_BELOW

`Static` CLOSE_GAP_TYPE_NONE

`Private` areBothValuesOnRequiredPlaneSide

`Optional` onRawSegmentsDetected?: ((rawSegmentsDoNotModifiy) => void)

`Optional` pathDetectEpsilon?: number

`Optional` pointEliminationEpsilon?: number

`Optional` useTriangles?: boolean

`Private` findHeight4FaceIntersectionLine

`Private` findHeightFaceIntersectionLines

`Private` findHeighteFace3IntersectionLine

`Private` getLerpRatio

`Private` isBetween

`Private` lerp