NearestGridSurface Class

public sealed class NearestGridSurface : GridSurface

Public NotInheritable Class NearestGridSurface
	Inherits GridSurface

public ref class NearestGridSurface sealed : public GridSurface

[<SealedAttribute>]
type NearestGridSurface = 
    class
        inherit GridSurface
    end

Inheritance

Object  →  Surface  →  GridSurface  →  NearestGridSurface

This surface performs nearest-neighbor interpolation by selecting the value at the closest grid point to the query point. The interpolated function is piecewise constant and discontinuous at cell boundaries.

Characteristics:

• Continuity: Discontinuous (piecewise constant)
• Smoothness: C^-1 (no derivatives defined at boundaries)
• Performance: Fastest grid interpolation method, O(log N) per query via binary search
• Gradient: Zero everywhere except at measure-zero boundaries

When to use:

• Categorical or discrete data: When interpolating classification labels, flags, or other discrete values where smooth interpolation is inappropriate.
• Maximum performance: When speed is critical and smoothness is not required, such as fast lookups in large tabulated functions.
• Visualization: For pixel-perfect rendering where each grid cell should have a uniform appearance (e.g., heatmaps with distinct cells).
• Debugging: To verify grid coverage and identify regions with sparse data.

Alternatives:

• LinearGridSurface: Use for continuous data where smoothness is desired. Provides C⁰ continuity with only modest performance cost.
• CubicGridSurface2D or CubicGridSurface3D: Use for 2D/3D data requiring smooth derivatives (C² continuity).
• TensorSplineGridSurface: Use for N-dimensional smooth interpolation with C¹ continuity and custom boundary conditions.

Applications:

• Image resampling with nearest-neighbor (pixel replication)
• Voxel rendering in medical imaging or volumetric displays
• Lookup tables for discrete states or categories
• Real-time applications requiring minimal latency
• Preserving exact integer or enum values during resampling

Creating instances: Use GridNearestInterpolator(IReadOnlyList<IReadOnlyList<Double>>, IReadOnlyList<Double>, ExtrapolationMode) factory methods to create instances of this class.

Reference