Skip to content

MagneticDeclinationAdornmentLayer

Namespace: ThinkGeo.Core

Draws a magnetic declination diagram that compares true, magnetic, and grid north at the map center.

public class MagneticDeclinationAdornmentLayer : AdornmentLayer

Inheritance object → LayerBase → Layer → AdornmentLayer → MagneticDeclinationAdornmentLayer

Properties

GridNorthLineStyle

Gets or sets the style used to render the grid north line.

public LineStyle GridNorthLineStyle { get; set; }

Property Value

LineStyle

TrueNorthLineStyle

Gets or sets the style used to render the true north line.

public LineStyle TrueNorthLineStyle { get; set; }

Property Value

LineStyle

MagneticNorthLineStyle

Gets or sets the style used to render the magnetic north line.

public LineStyle MagneticNorthLineStyle { get; set; }

Property Value

LineStyle

TextStyle

Gets or sets the text style used for annotations within the diagram.

public TextStyle TextStyle { get; set; }

Property Value

TextStyle

TrueNorthPointStyle

Gets or sets the symbol style used to highlight true north.

public PointStyle TrueNorthPointStyle { get; set; }

Property Value

PointStyle

ElevationUnit

Gets or sets the measurement unit used for the MagneticDeclinationAdornmentLayer.Elevation value.

public DistanceUnit ElevationUnit { get; set; }

Property Value

DistanceUnit

MagneticFieldPathFilename

Gets the file path for the International Geomagnetic Reference Field (IGRF) model backing this layer.

public string MagneticFieldPathFilename { get; }

Property Value

string

Elevation

Gets or sets the elevation used when computing declination values.

public double Elevation { get; set; }

Property Value

double

SampleDateTime

Gets or sets the sample date for which the declination is calculated.

public DateTime SampleDateTime { get; set; }

Property Value

DateTime

UpdateWhilePanning

public bool UpdateWhilePanning { get; }

Property Value

bool

Width

Gets or sets the adornment width in pixels. Deprecated; use .

public float Width { get; set; }

Property Value

float

ResizeScale

Gets or sets the resize scale applied to the adornment layer.

public float ResizeScale { get; set; }

Property Value

float

Remarks:

A value of 1 preserves the original size; values greater than 1 enlarge; values less than 1 shrink.

Height

Gets or sets the adornment height in pixels. Deprecated; use .

public float Height { get; set; }

Property Value

float

DragMode

Gets or sets how the adornment responds to drag operations.

public AdornmentDragMode DragMode { get; set; }

Property Value

AdornmentDragMode

ResizeMode

public AdornmentResizeMode ResizeMode { get; set; }

Property Value

AdornmentResizeMode

BackgroundMask

Gets or sets the fill/outline style drawn behind the adornment content.

public AreaStyle BackgroundMask { get; set; }

Property Value

AreaStyle

Location

This property gets and sets the drawing location of the AdornmentLayer.

public AdornmentLocation Location { get; set; }

Property Value

AdornmentLocation

XOffsetInPixel

This property gets and sets the X pixel offset for the AdornmentLayer.

public float XOffsetInPixel { get; set; }

Property Value

float

Remarks:

This property allows you to specify an X offset. It is useful, when combined with a Y offset, to do things like modify the location of the adornment.

YOffsetInPixel

This property gets and sets the Y pixel offset for the AdornmentLayer.

public float YOffsetInPixel { get; set; }

Property Value

float

Remarks:

This property allows you to specify a Y offset. It is useful, when combined with an X offset, to do things like modify the location of the adornment.

RequestDrawingInterval

Gets or sets the interval between automatic draw requests. Obsolete.

public TimeSpan RequestDrawingInterval { get; set; }

Property Value

TimeSpan

Name

Gets or sets the display name for the layer.

public string Name { get; set; }

Property Value

string
The name used to identify the layer within UI components such as legends.

Remarks:

The name is user defined. Assign a descriptive value so tooling such as legends and layer lists can surface a meaningful label to end users.

IsOpen

Gets a value indicating whether the layer is currently open.

public bool IsOpen { get; }

Property Value

bool
true if the layer has completed its open routine; otherwise, false.

Remarks:

This method is the concrete wrapper for the abstract method IsOpenCore. Various methods on the Layer require that it be in an open state. If one of those methods is called when the state is not open, then the method will throw an exception. To enter the open state, you must call the Layer Open method. The method will raise an exception if the current Layer is already open.

As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.

IsVisible

Gets or sets a value indicating whether the layer is visible.

public bool IsVisible { get; set; }

Property Value

bool
true to draw the layer; otherwise, false.

Remarks:

If this property is set to false, the layer will not draw. We ensure this in the Draw method. This is useful for legends and other controls that control the visibility of layers.

DrawingTime

Gets the last recorded drawing time for the layer.

public TimeSpan DrawingTime { get; protected set; }

Property Value

TimeSpan
The duration of the most recent draw operation.

Remarks:

We track the drawing time for the layer and report it back in this method. This is useful for determining the speed of various layers.

Projection

Gets the projection of the layer.

public Projection Projection { get; set; }

Property Value

Projection

DrawingExceptionMode

Gets or sets how drawing exceptions are handled when the layer renders.

public DrawingExceptionMode DrawingExceptionMode { get; set; }

Property Value

DrawingExceptionMode

Background

Gets or sets the background color used when rendering the layer.

public GeoColor Background { get; set; }

Property Value

GeoColor
The fill applied to areas not covered by layer content.

Transparency

Gets or sets the amount of transparency applied to the rendered image.

public float Transparency { get; set; }

Property Value

float
A value between 0 (fully transparent) and 255 (fully opaque).

BlueTranslation

Gets or sets the intensity adjustment applied to the blue channel.

public float BlueTranslation { get; set; }

Property Value

float
A value between -255 and 255 representing the blue channel translation.

RedTranslation

Gets or sets the intensity adjustment applied to the red channel.

public float RedTranslation { get; set; }

Property Value

float
A value between -255 and 255 representing the red channel translation.

GreenTranslation

Gets or sets the intensity adjustment applied to the green channel.

public float GreenTranslation { get; set; }

Property Value

float
A value between -255 and 255 representing the green channel translation.

KeyColors

Gets the collection of key colors that should be rendered as transparent.

public Collection<GeoColor> KeyColors { get; }

Property Value

Collection<GeoColor>

Remarks:

Attempting to access this collection when the associated GeoCanvas does not support key colors (see GeoCanvas.SupportKeyColor) results in an exception. Add colors to this collection to ensure they render as transparent.

IsNegative

Gets or sets a value indicating whether the image should be rendered with inverted colors.

public bool IsNegative { get; set; }

Property Value

bool
true to invert the color channels; otherwise, false.

IsGrayscale

Gets or sets a value indicating whether the image should be converted to grayscale prior to rendering.

public bool IsGrayscale { get; set; }

Property Value

bool
true to apply a grayscale filter; otherwise, false.

HasBoundingBox

Gets a value indicating whether the layer supports retrieving its bounding box.

public bool HasBoundingBox { get; }

Property Value

bool

Remarks:

When this property is false, calls to or GetFullExtent throw an exception. The default implementation returns false.

ThreadSafe

Gets or sets the threading guarantees provided by the layer implementation.

public ThreadSafetyLevel ThreadSafe { get; set; }

Property Value

ThreadSafetyLevel
The level of thread safety that callers can expect when interacting with the layer.

ColorMappings

Gets the color translation map that will be applied when rendering the layer.

public Dictionary<GeoColor, GeoColor> ColorMappings { get; }

Property Value

Dictionary<GeoColor, GeoColor>

WrappingMode

Gets or sets how the layer wraps when the map extent crosses world boundaries.

public WrappingMode WrappingMode { get; set; }

Property Value

WrappingMode

WrappingExtent

Gets or sets the geographic extent to use when wrapping is enabled.

public RectangleShape WrappingExtent { get; set; }

Property Value

RectangleShape

Constructors

MagneticDeclinationAdornmentLayer()

Initializes a new instance of the MagneticDeclinationAdornmentLayer class.

public MagneticDeclinationAdornmentLayer()

MagneticDeclinationAdornmentLayer(ScreenPointF)

Initializes the layer and positions it using explicit screen offsets.

public MagneticDeclinationAdornmentLayer(ScreenPointF startPoint)

Parameters

startPoint ScreenPointF
Starting location in screen pixels relative to the upper-left corner.

MagneticDeclinationAdornmentLayer(AdornmentLocation)

Initializes the layer with the given adornment location.

public MagneticDeclinationAdornmentLayer(AdornmentLocation adornmentLocation)

Parameters

adornmentLocation AdornmentLocation
Position of the declination diagram on the map.

MagneticDeclinationAdornmentLayer(string, AdornmentLocation)

Initializes the layer and configures the magnetic field model file path.

public MagneticDeclinationAdornmentLayer(string magneticFieldPathFilename, AdornmentLocation adornmentLocation)

Parameters

magneticFieldPathFilename string
Path to the magnetic model file; leave empty to use the embedded resource.

adornmentLocation AdornmentLocation
Position of the declination diagram on the map.

Methods

GetSelectionLocationCore(float, float, float, float)

Returns the selection origin for hit-testing.

protected ScreenPointF GetSelectionLocationCore(float mapWidth, float mapHeight, float adornmentWidth, float adornmentHeight)

Parameters

mapWidth float

mapHeight float

adornmentWidth float

adornmentHeight float

Returns

ScreenPointF

GetWidthCore()

Returns a reasonable width for hit-testing and selection based on the configured styles.

protected float GetWidthCore()

Returns

float

GetHeightCore()

Returns a reasonable height for hit-testing and selection based on the configured styles.

protected float GetHeightCore()

Returns

float

OnStreamLoading(StreamLoadingEventArgs)

This method allows you to raise the StreamLoading event.

protected void OnStreamLoading(StreamLoadingEventArgs e)

Parameters

e StreamLoadingEventArgs
This parameter represents the event arguments you want to raise the StreamLoading event with.

Returns

void
None

Remarks:

This method allows you to raise the StreamLoading event. Normally events are not accessible to derived classes, so we exposed a way to raise the event as necessary through this protected method.

GetDrawingLocation(GeoCanvas, float, float)

Calculates the screen position of the declination diagram based on the configured AdornmentLayer.Location.

public ScreenPointF GetDrawingLocation(GeoCanvas canvas, float adornmentWidth, float adornmentHeight)

Parameters

canvas GeoCanvas
The current drawing canvas.

adornmentWidth float
Width of the adornment.

adornmentHeight float
Height of the adornment.

Returns

ScreenPointF
The screen coordinate where the adornment should be drawn.

GetMagneticDeclination(Feature, double, DistanceUnit, DateTime)

Calculates magnetic declination for the specified feature using the embedded magnetic field model.

public static MagneticDeclination GetMagneticDeclination(Feature pointFeature, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime)

Parameters

pointFeature Feature
Feature whose location is evaluated; must contain a .

elevation double
Elevation value associated with the point.

elevationUnit DistanceUnit
Unit of the elevation value.

sampleDateTime DateTime
Date of interest.

Returns

MagneticDeclination
A populated object.

GetMagneticDeclination(Feature, double, DistanceUnit, DateTime, string)

Calculates magnetic declination for the specified feature using a magnetic model from disk.

public static MagneticDeclination GetMagneticDeclination(Feature pointFeature, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, string magneticFieldPathFilename)

Parameters

pointFeature Feature
Feature whose location is evaluated; must contain a .

elevation double
Elevation value associated with the point.

elevationUnit DistanceUnit
Unit of the elevation value.

sampleDateTime DateTime
Date of interest.

magneticFieldPathFilename string
Path to the magnetic model file.

Returns

MagneticDeclination

GetMagneticDeclination(Feature, double, DistanceUnit, DateTime, Stream)

Calculates magnetic declination for the specified feature using the provided magnetic model stream.

public static MagneticDeclination GetMagneticDeclination(Feature pointFeature, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, Stream magneticFieldStream)

Parameters

pointFeature Feature

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

magneticFieldStream Stream

Returns

MagneticDeclination

GetMagneticDeclination(PointShape, double, DistanceUnit, DateTime)

Calculates magnetic declination for the supplied point using the embedded magnetic field model.

public static MagneticDeclination GetMagneticDeclination(PointShape point, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime)

Parameters

point PointShape

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

Returns

MagneticDeclination

GetMagneticDeclination(PointShape, double, DistanceUnit, DateTime, string)

Calculates magnetic declination for the supplied point using a magnetic model from disk.

public static MagneticDeclination GetMagneticDeclination(PointShape point, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, string magneticFieldPathFilename)

Parameters

point PointShape

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

magneticFieldPathFilename string

Returns

MagneticDeclination

GetMagneticDeclination(PointShape, double, DistanceUnit, DateTime, Stream)

Calculates magnetic declination for the supplied point using the provided magnetic model stream.

public static MagneticDeclination GetMagneticDeclination(PointShape point, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, Stream magneticFieldStream)

Parameters

point PointShape

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

magneticFieldStream Stream

Returns

MagneticDeclination

GetMagneticDeclination(double, double, double, DistanceUnit, DateTime)

Calculates magnetic declination using the embedded model and raw geographic coordinates.

public static MagneticDeclination GetMagneticDeclination(double x, double y, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime)

Parameters

x double

y double

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

Returns

MagneticDeclination

GetMagneticDeclination(double, double, double, DistanceUnit, DateTime, string)

Calculates magnetic declination using a model loaded from disk and raw geographic coordinates.

public static MagneticDeclination GetMagneticDeclination(double x, double y, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, string magneticFieldPathFilename)

Parameters

x double

y double

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

magneticFieldPathFilename string

Returns

MagneticDeclination

GetMagneticDeclination(double, double, double, DistanceUnit, DateTime, Stream)

Calculates magnetic declination using a supplied model stream and raw geographic coordinates.

public static MagneticDeclination GetMagneticDeclination(double x, double y, double elevation, DistanceUnit elevationUnit, DateTime sampleDateTime, Stream magneticFieldStream)

Parameters

x double

y double

elevation double

elevationUnit DistanceUnit

sampleDateTime DateTime

magneticFieldStream Stream

Returns

MagneticDeclination

OpenCore()

Provides the overridable implementation that opens the instance and initializes the resources it depends on.

protected void OpenCore()

Returns

void

CloseCore()

Provides the overridable implementation that closes the instance and releases any resources it holds.

protected void CloseCore()

Returns

void

DrawCore(GeoCanvas, Collection<SimpleCandidate>)

Renders the declination diagram on the specified canvas.

protected void DrawCore(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

canvas GeoCanvas

labelsInAllLayers Collection<SimpleCandidate>

Returns

void

Events

StreamLoading

Raised when the layer needs access to the magnetic field model stream, allowing callers to supply their own data.

public event EventHandler<StreamLoadingEventArgs> StreamLoading;

DrawingProgressChanged

Occurs as the layer reports drawing progress (useful for async or tiled rendering scenarios).

public event EventHandler<DrawingProgressChangedEventArgs> DrawingProgressChanged;

RequestedDrawing

Raised after the drawing buffer elapses so consumers can handle a legacy drawing cycle. Obsolete.

public event EventHandler<RequestedDrawingLayerEventArgs> RequestedDrawing;

RequestingDrawing

Raised before the drawing buffer elapses so consumers can cancel a legacy drawing operation. Obsolete.

public event EventHandler<RequestingDrawingLayerEventArgs> RequestingDrawing;

DrawingException

Occurs when the DrawingException event is raised.

public event EventHandler<DrawingExceptionLayerEventArgs> DrawingException;

DrawnException

Occurs when the DrawnException event is raised.

public event EventHandler<DrawnExceptionLayerEventArgs> DrawnException;