Class: QgsMapToolIdentify

Map tool for identifying features in layers.

After the tool is used to select a point, this map tool performs the identification:

• for raster layers shows value of underlying pixel

• for vector layers shows feature attributes within search radius (allows editing values when vector layer is in editing mode)

Class Hierarchy

Base classes

QgsMapTool	Abstract base class for all map tools.
QObject

Subclasses

QgsMapToolIdentifyFeature

A map tool to identify a feature on a chosen layer.

Methods

derivedAttributesForPoint	Returns derived attributes map for a clicked point in map coordinates.
formatChanged
identify	Performs the identification.
identifyLayer	Call the right method depending on layer type
identifyMenu	Returns a pointer to the identify menu which will be used in layer selection mode this menu can also be customized
identifyMeshLayer	Identifies data from active scalar and vector dataset from the mesh layer
identifyRasterLayer	Performs the identification against a given raster layer.
identifyVectorLayer	Performs the identification against a given vector layer.
restoreCanvasPropertiesOverrides	Clears canvas properties overrides previously set with setCanvasPropertiesOverrides()
restorePropertiesOverrides	Clears canvas properties overrides previously set with setPropertiesOverrides()
setCanvasPropertiesOverrides	Overrides some map canvas properties inside the map tool for the upcoming identify requests.
setPropertiesOverrides	Overrides some map canvas properties inside the map tool for the upcoming identify requests.

Signals

changedRasterResults	Emitted when the format of raster results is changed and need to be updated in user-facing displays.
identifyMessage	Emitted when the identify operation needs to show a user-facing message
identifyProgress	Emitted when the identify action progresses.

Attributes

ActiveLayer
AllLayers
DefaultQgsSetting
LayerSelection
MeshLayer
PointCloudLayer
RasterLayer
TopDownAll
TopDownStopAtFirst
VectorLayer
VectorTileLayer

class qgis.gui.QgsMapToolIdentify

Bases: QgsMapTool

__init__(canvas: QgsMapCanvas | None)

constructor

Parameters:

canvas (Optional[QgsMapCanvas])

ActiveLayer = 0

AllLayers = 31

DefaultQgsSetting = -1

class IdentifyMode

Bases: int

class IdentifyProperties

class IdentifyProperties(a0: QgsMapToolIdentify.IdentifyProperties)

Bases: object

searchRadiusMapUnits: float

Identify search radius is map units. Use negative value to ignore

skip3DLayers: bool

Skip identify results from layers that have a 3d renderer set

class IdentifyResult

class IdentifyResult(layer: QgsMapLayer | None, feature: QgsFeature, derivedAttributes: Dict[str | None, str | None])

class IdentifyResult(layer: QgsMapLayer | None, label: str | None, attributes: Dict[str | None, str | None], derivedAttributes: Dict[str | None, str | None])

class IdentifyResult(layer: QgsMapLayer | None, label: str | None, fields: QgsFields, feature: QgsFeature, derivedAttributes: Dict[str | None, str | None])

class IdentifyResult(a0: QgsMapToolIdentify.IdentifyResult)

Bases: object

mAttributes

mDerivedAttributes

mFeature

mFields

mLabel

mLayer

mParams

LayerSelection = 3

class LayerType

class LayerType(f: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type)

class LayerType(a0: QgsMapToolIdentify.LayerType)

Bases: object

MeshLayer = 4

PointCloudLayer = 16

RasterLayer = 2

TopDownAll = 2

TopDownStopAtFirst = 1

class Type

Bases: int

VectorLayer = 1

VectorTileLayer = 8

signal changedRasterResults(results: List[QgsMapToolIdentify.IdentifyResult])

Emitted when the format of raster results is changed and need to be updated in user-facing displays.

Parameters:

results (List[QgsMapToolIdentify.IdentifyResult])

derivedAttributesForPoint(self, point: QgsPoint) → Dict[str, str]

Returns derived attributes map for a clicked point in map coordinates. May be 2D or 3D point.

Parameters:

point (QgsPoint)

Return type:

Dict[str, str]

formatChanged(self, layer: QgsRasterLayer | None)

Parameters:

layer (Optional[QgsRasterLayer])

identify(self, x: int, y: int, layerList: Iterable[QgsMapLayer] = [], mode: QgsMapToolIdentify.IdentifyMode = QgsMapToolIdentify.DefaultQgsSetting, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → List[QgsMapToolIdentify.IdentifyResult]

Performs the identification.

Parameters:

• x (int) – x coordinates of mouseEvent

• y (int) – y coordinates of mouseEvent

• layerList (Iterable[QgsMapLayer] = []) – Performs the identification within the given list of layers. Default value is an empty list, i.e. uses all the layers.

• mode (QgsMapToolIdentify.IdentifyMode = QgsMapToolIdentify.DefaultQgsSetting) – Identification mode. Can use QGIS default settings or a defined mode. Default mode is DefaultQgsSetting.

• identifyContext (QgsIdentifyContext = QgsIdentifyContext()) – Identify context object.

Return type:

List[QgsMapToolIdentify.IdentifyResult]

Returns:

a list of IdentifyResult

identify(self, x: int, y: int, mode: QgsMapToolIdentify.IdentifyMode, layerType: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type = QgsMapToolIdentify.AllLayers, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → List[QgsMapToolIdentify.IdentifyResult]

Performs the identification. To avoid being forced to specify IdentifyMode with a list of layers this has been made private and two publics methods are offered

Parameters:

• x (int) – x coordinates of mouseEvent

• y (int) – y coordinates of mouseEvent

• mode (QgsMapToolIdentify.IdentifyMode) – Identification mode. Can use QGIS default settings or a defined mode.

• layerType (Union[QgsMapToolIdentify.LayerType, QgsMapToolIdentify.Type] = QgsMapToolIdentify.AllLayers) – Only performs identification in a certain type of layers (raster, vector, mesh). Default value is AllLayers.

• identifyContext (QgsIdentifyContext = QgsIdentifyContext()) – Identify context object.

Return type:

List[QgsMapToolIdentify.IdentifyResult]

Returns:

a list of IdentifyResult

identify(self, geometry: QgsGeometry, mode: QgsMapToolIdentify.IdentifyMode, layerType: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → List[QgsMapToolIdentify.IdentifyResult]

Performs identification based on a geometry (in map coordinates)

Parameters:

• geometry (QgsGeometry)

• mode (QgsMapToolIdentify.IdentifyMode)

• layerType (Union[QgsMapToolIdentify.LayerType, QgsMapToolIdentify.Type])

• identifyContext (QgsIdentifyContext = QgsIdentifyContext())

Return type:

List[QgsMapToolIdentify.IdentifyResult]

identify(self, geometry: QgsGeometry, mode: QgsMapToolIdentify.IdentifyMode, layerList: Iterable[QgsMapLayer], layerType: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → List[QgsMapToolIdentify.IdentifyResult]

Performs identification based on a geometry (in map coordinates)

Parameters:

• geometry (QgsGeometry)

• mode (QgsMapToolIdentify.IdentifyMode)

• layerList (Iterable[QgsMapLayer])

• layerType (Union[QgsMapToolIdentify.LayerType, QgsMapToolIdentify.Type])

• identifyContext (QgsIdentifyContext = QgsIdentifyContext())

Return type:

List[QgsMapToolIdentify.IdentifyResult]

identify(self, x: int, y: int, mode: QgsMapToolIdentify.IdentifyMode, layerList: Iterable[QgsMapLayer], layerType: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type = QgsMapToolIdentify.AllLayers, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → List[QgsMapToolIdentify.IdentifyResult]

Performs the identification. To avoid being forced to specify IdentifyMode with a list of layers this has been made private and two publics methods are offered

Parameters:

• x (int) – x coordinates of mouseEvent

• y (int) – y coordinates of mouseEvent

• mode (QgsMapToolIdentify.IdentifyMode) – Identification mode. Can use QGIS default settings or a defined mode.

• layerList (Iterable[QgsMapLayer]) – Performs the identification within the given list of layers.

• layerType (Union[QgsMapToolIdentify.LayerType, QgsMapToolIdentify.Type] = QgsMapToolIdentify.AllLayers) – Only performs identification in a certain type of layers (raster, vector, mesh).

• identifyContext (QgsIdentifyContext = QgsIdentifyContext()) – Identify context object.

Return type:

List[QgsMapToolIdentify.IdentifyResult]

Returns:

a list of IdentifyResult

identifyLayer(self, results: Iterable[QgsMapToolIdentify.IdentifyResult] | None, layer: QgsMapLayer | None, point: QgsPointXY, viewExtent: QgsRectangle, mapUnitsPerPixel: float, layerType: QgsMapToolIdentify.LayerType | QgsMapToolIdentify.Type = QgsMapToolIdentify.AllLayers, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → bool

Call the right method depending on layer type

Parameters:

• results (Optional[Iterable[QgsMapToolIdentify.IdentifyResult]])

• layer (Optional[QgsMapLayer])

• point (QgsPointXY)

• viewExtent (QgsRectangle)

• mapUnitsPerPixel (float)

• layerType (Union[QgsMapToolIdentify.LayerType, QgsMapToolIdentify.Type] = QgsMapToolIdentify.AllLayers)

• identifyContext (QgsIdentifyContext = QgsIdentifyContext())

Return type:

bool

identifyMenu(self) → QgsIdentifyMenu | None

Returns a pointer to the identify menu which will be used in layer selection mode this menu can also be customized

Return type:

Optional[QgsIdentifyMenu]

identifyMeshLayer(self, results: Iterable[QgsMapToolIdentify.IdentifyResult] | None, layer: QgsMeshLayer | None, point: QgsPointXY, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → bool

Identifies data from active scalar and vector dataset from the mesh layer

Works only if layer was already rendered (triangular mesh is created)

Added in version 3.6.

Parameters:

• results (Optional[Iterable[QgsMapToolIdentify.IdentifyResult]])

• layer (Optional[QgsMeshLayer])

• point (QgsPointXY)

• identifyContext (QgsIdentifyContext = QgsIdentifyContext())

Return type:

bool

signal identifyMessage(message: str)

Emitted when the identify operation needs to show a user-facing message

Parameters:

message (str) – Message to show to the user

signal identifyProgress(processed: int, total: int)

Emitted when the identify action progresses.

Parameters:

• processed (int) – number of objects processed so far

• total (int) – total number of objects to process

identifyRasterLayer(self, results: Iterable[QgsMapToolIdentify.IdentifyResult] | None, layer: QgsRasterLayer | None, point: QgsPointXY, viewExtent: QgsRectangle, mapUnitsPerPixel: float, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → bool

Performs the identification against a given raster layer.

Parameters:

• results (Optional[Iterable[QgsMapToolIdentify.IdentifyResult]]) – list of identify results

• layer (Optional[QgsRasterLayer]) – raster layer to identify from

• point (QgsPointXY) – point coordinate to identify

• viewExtent (QgsRectangle) – view extent

• mapUnitsPerPixel (float) – map units per pixel value

• identifyContext (QgsIdentifyContext = QgsIdentifyContext()) – identify context object

Return type:

bool

identifyVectorLayer(self, results: Iterable[QgsMapToolIdentify.IdentifyResult] | None, layer: QgsVectorLayer | None, point: QgsPointXY, identifyContext: QgsIdentifyContext = QgsIdentifyContext()) → bool

Performs the identification against a given vector layer.

Parameters:

• results (Optional[Iterable[QgsMapToolIdentify.IdentifyResult]]) – list of identify results

• layer (Optional[QgsVectorLayer]) – raster layer to identify from

• point (QgsPointXY) – point coordinate to identify

• identifyContext (QgsIdentifyContext = QgsIdentifyContext()) – identify context object

Return type:

bool

restoreCanvasPropertiesOverrides(self)

Clears canvas properties overrides previously set with setCanvasPropertiesOverrides()

See also

setCanvasPropertiesOverrides()

Added in version 3.4.

Deprecated since version 3.42: Use restorePropertiesOverrides() instead.

restorePropertiesOverrides(self)

Clears canvas properties overrides previously set with setPropertiesOverrides()

See also

setPropertiesOverrides()

Added in version 3.42.

setCanvasPropertiesOverrides(self, searchRadiusMapUnits: float)

Overrides some map canvas properties inside the map tool for the upcoming identify requests.

This is useful when the identification is triggered by some other piece of GUI like a 3D map view and some properties like search radius need to be adjusted so that identification returns correct results. When the custom identification has finished, restoreCanvasPropertiesOverrides() should be called to erase any overrides.

Parameters:

searchRadiusMapUnits (float) – The overridden search radius in map units

See also

restoreCanvasPropertiesOverrides()

Added in version 3.4.

Deprecated since version 3.42: Use setPropertiesOverrides() instead.

setPropertiesOverrides(self, overrides: QgsMapToolIdentify.IdentifyProperties)

Overrides some map canvas properties inside the map tool for the upcoming identify requests.

This is useful when the identification is triggered by some other piece of GUI like a 3D map view and some properties like search radius need to be adjusted so that identification returns correct results. When the custom identification has finished, restorePropertiesOverrides() should be called to erase any overrides.

Parameters:

overrides (QgsMapToolIdentify.IdentifyProperties) – The identify tool properties that will be overridden

Added in version 3.42.