Class: QgsInterpolator

Interface class for interpolations.

Interpolators take the vertices of a vector layer as base data. The z-Value can be an attribute or the z-coordinates in case of 3D types.

Note

This is an abstract class, with methods which must be implemented by a subclass.

The following methods must be implemented: interpolatePoint()

Class Hierarchy

Inheritance diagram of qgis.analysis.QgsInterpolator

Subclasses

QgsIDWInterpolator

Inverse distance weight interpolator.

QgsTinInterpolator

Interpolation in a triangular irregular network.
class qgis.analysis.QgsInterpolator[source]

Bases: object

class LayerData

Bases: object

A source together with the information about interpolation attribute / z-coordinate interpolation and the type (point, structure line, breakline)

interpolationAttribute: int
source: QgsFeatureSource
sourceType: QgsInterpolator.SourceType
transformContext: QgsCoordinateTransformContext
valueSource: QgsInterpolator.ValueSource
class Result(*values)

Bases: IntEnum

Result of an interpolation operation

  • Success: Operation was successful

  • Canceled: Operation was manually canceled

  • InvalidSource: Operation failed due to invalid source

  • FeatureGeometryError: Operation failed due to invalid feature geometry

Canceled = 1
FeatureGeometryError = 3
InvalidSource = 2
Success = 0
class SourceType(*values)

Bases: IntEnum

Describes the type of input data

  • Points: Point source

    Available as QgsInterpolator.SourcePoints in older QGIS releases.

  • StructureLines: Structure lines

    Available as QgsInterpolator.SourceStructureLines in older QGIS releases.

  • BreakLines: Break lines

    Available as QgsInterpolator.SourceBreakLines in older QGIS releases.

class ValueSource(*values)

Bases: IntEnum

Source for interpolated values from features

  • Attribute: Take value from feature’s attribute

    Available as QgsInterpolator.ValueAttribute in older QGIS releases.

  • Z: Use feature’s geometry Z values for interpolation

    Available as QgsInterpolator.ValueZ in older QGIS releases.

  • M: Use feature’s geometry M values for interpolation

    Available as QgsInterpolator.ValueM in older QGIS releases.

cacheBaseData(self, feedback: QgsFeedback | None = None) → QgsInterpolator.Result[source]

Caches the vertex and value data from the provider. All the vertex data will be held in virtual memory.

An optional feedback argument may be specified to allow cancellation and progress reports from the cache operation.

Return type:

QgsInterpolator.Result

Returns:

Success in case of success

Parameters:

feedback (Optional[QgsFeedback] = None)

abstract interpolatePoint(self, x: float, y: float, feedback: QgsFeedback | None = None)[source]

Calculates interpolation value for map coordinates x, y

Parameters:

  • x (float) – x-coordinate (in map units)

  • y (float) – y-coordinate (in map units)

  • feedback (Optional[QgsFeedback] = None) -> (int) – optional feedback object for progress and cancellation support

Returns:

  • 0 in case of success

  • result: interpolation result