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WmsAsyncLayer

Namespace: ThinkGeo.Core

Represents an object that encapsulates a Web Map Service (WMS) layer.

public class WmsAsyncLayer : WebBasedAsyncLayer, IHttpRequestService, IWmsEntity

Inheritance object → LayerBase → AsyncLayer → WebBasedAsyncLayer → WmsAsyncLayer
Implements IHttpRequestService, IWmsEntity

Remarks:

A Web Map Service (WMS) produces maps of spatially referenced data dynamically from geographic information. This International Standard defines a "map" to be a portrayal of geographic information as a digital image file suitable for display on a computer screen. A map is not the data itself. WMS-produced maps are generally rendered in a pictorial format such as PNG, GIF or JPEG, or occasionally as vector-based graphical elements in Scalable Vector Graphics (SVG) or Web Computer Graphics Metafile (WebCGM) formats.

Properties

ActiveLayerNames

This property allows the active layers requested from the client to be shown on the map.

public Collection<string> ActiveLayerNames { get; }

Property Value

Collection<string>

Remarks:

When requesting a map, a client may specify the layers to be shown on the map.

ActiveStyleNames

This property allows the active styles requested from the client to be shown on the map.

public Collection<string> ActiveStyleNames { get; }

Property Value

Collection<string>

Remarks:

When requesting a map, a client may specify the styles to be shown on the map.

Uri

This property specifies the URI of the WMS server.

public Uri Uri { get; set; }

Property Value

Uri

Version

This property gets the version.

public string Version { get; }

Property Value

string

IsTransparent

This property gets or sets whether the response map image's background color is transparent or not.

public bool IsTransparent { get; set; }

Property Value

bool

OutputFormat

This property gets or sets the desired output format for the map being requested from the WMS.

public string OutputFormat { get; set; }

Property Value

string

Remarks:

When requesting a map, a client may specify the output format in which to show the map. Formats are specified as MIME types such as "image/gif" or "image/png".

Crs

This property gets or sets the projected or geographic coordinate reference system to be used.

public string Crs { get; set; }

Property Value

string

Exceptions

This property indicates the format in which the client wishes to be notified of service exceptions.

public string Exceptions { get; set; }

Property Value

string

Remarks:

Upon receiving a request that is invalid according to the OGC standard, the server shall issue a service exception report. The service report is meant to describe to the client application or its human user the reason(s) that the request is invalid.

Parameters

This property specifies a dictionary used to update the request sent from the client to the WMS server.

public Dictionary<string, string> Parameters { get; }

Property Value

Dictionary<string, string>

AxisOrder

This property specifies the order in which the coordinate axes are arranged when making requests to a Web Map Service (WMS) server. It is used to define the spatial reference system for the layer.

public WmsAxisOrder AxisOrder { get; set; }

Property Value

WmsAxisOrder

ProjectionConverter

Gets or sets the ProjectionConverter.

public ProjectionConverter ProjectionConverter { get; set; }

Property Value

ProjectionConverter

FastMode

This property gets or sets whether request and parse capabilities.

public bool FastMode { get; set; }

Property Value

bool

CapabilitiesCacheTimeout

The timeout for Capabilities Cache, its 10 minutes by default

public TimeSpan CapabilitiesCacheTimeout { get; set; }

Property Value

TimeSpan

HasBoundingBox

This property checks to see if a Layer has a BoundingBox or not. If it has no BoundingBox, it will throw an exception when you call the GetBoundingBox() and GetFullExtent() APIs.

public bool HasBoundingBox { get; }

Property Value

bool

Remarks:

The override in the WmsRasterLayer sets it to true.

HttpClient

Gets or sets the HTTP client reused for outbound requests.

public HttpClient HttpClient { get; set; }

Property Value

HttpClient

WebProxy

Gets or sets the proxy through which all HTTP requests should be routed.

public IWebProxy WebProxy { get; set; }

Property Value

IWebProxy

TimeoutInSeconds

Gets or sets the request timeout, in seconds.

public int TimeoutInSeconds { get; set; }

Property Value

int

Credentials

Gets or sets the credential provider used when authenticating HTTP requests.

public ICredentials Credentials { get; set; }

Property Value

ICredentials

UserAgent

This property allows you to specify a custom user-agent request header when making requests to a Web server. This header provides information about the client application or device and can be useful for server-side logging and analytics.

public string UserAgent { get; set; }

Property Value

string

UpperThreshold

This property gets and sets the upper threshold in the scale at which to display the image.

public double UpperThreshold { get; set; }

Property Value

double
This property gets the upper threshold in the scale at which to display the image.

Remarks:

Above the upper threshold in scale, the image will not be displayed. This, in conjunction with the LowerThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is 0. This means the image should always display.

LowerThreshold

This property gets and sets the lower threshold in the scale at which to display the image.

public double LowerThreshold { get; set; }

Property Value

double
This property gets the lower threshold in the scale at which to display the image.

Remarks:

Below the lower threshold in scale, the image will not be displayed. This, in conjunction with the UpperThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is 0. This means the image should always display.

UpperScale

This property gets and sets the upper threshold in the scale at which to display the image.

public double UpperScale { get; set; }

Property Value

double
This property gets the upper threshold in the scale at which to display the image.

Remarks:

Above the upper threshold in scale, the image will not be displayed. This, in conjunction with the LowerThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is 0. This means the image should always display.

LowerScale

This property gets and sets the lower threshold in the scale at which to display the image.

public double LowerScale { get; set; }

Property Value

double
This property gets the lower threshold in the scale at which to display the image.

Remarks:

Below the lower threshold in scale, the image will not be displayed. This, in conjunction with the UpperThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is 0. This means the image should always display.

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.

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

WmsAsyncLayer()

This is the constructor for the class. If you use this constructor, then you need to set the required properties manually.

public WmsAsyncLayer()

Remarks:

None

WmsAsyncLayer(Uri)

This is the constructor the for the class.

public WmsAsyncLayer(Uri uri)

Parameters

uri Uri
URI of the WMS server.

Remarks:

This constructor initializes a new WmsRasterSource and downloads and parses the service description. In an ASP.NET application, the service description is automatically cached for 24 hours when it is not specified.

WmsAsyncLayer(Uri, IWebProxy)

This is the constructor the for the class.

public WmsAsyncLayer(Uri uri, IWebProxy webProxy)

Parameters

uri Uri
URI of the WMS server.

webProxy IWebProxy
Proxy to use for the current WMS layer.

Remarks:

This constructor initializes a new WmsRasterSource and downloads and parses the service description. In an ASP.NET application, the service description is automatically cached for 24 hours when it is not specified.

WmsAsyncLayer(Uri, IWebProxy, string, WmsAxisOrder, string, bool)

This is the constructor the for the class.

public WmsAsyncLayer(Uri uri, IWebProxy webProxy, string crs, WmsAxisOrder axisOrder, string version, bool fastMode)

Parameters

uri Uri
URI of the WMS server.

webProxy IWebProxy
Proxy to use for the current WMS layer.

crs string
the projected or geographic coordinate reference system to be used.

axisOrder WmsAxisOrder
the axis order of the layer

version string
version of the WMS server

fastMode bool
whether request and parse capabilities

Remarks:

This constructor initializes a new WmsRasterSource and downloads and parses the service description In an ASP.NET application, the service description is automatically cached for 24 hours when it is not specified.

WmsAsyncLayer(Collection<WmsServerLayer>)

Initializes a new instance of the WmsAsyncLayer class.

public WmsAsyncLayer(Collection<WmsServerLayer> flatWmsServerLayers)

Parameters

flatWmsServerLayers Collection<WmsServerLayer>

Methods

OnRequestedImageException(RequestedImageExceptionEventArgs)

Performs on requested image exception.

protected void OnRequestedImageException(RequestedImageExceptionEventArgs e)

Parameters

e RequestedImageExceptionEventArgs
The e.

Returns

void

GetServerLayers()

This method returns all layers at the server side.

public Collection<WmsServerLayer> GetServerLayers()

Returns

Collection<WmsServerLayer>
The names of all layers at the server side.

Remarks:

None.

GetServerStyleNames()

This method returns the names of all styles at the server side.

public Collection<string> GetServerStyleNames()

Returns

Collection<string>
The names of all styles at the server side.

Remarks:

None.

GetServerOutputFormats()

This method returns the output format at the server side.

public Collection<string> GetServerOutputFormats()

Returns

Collection<string>
The output format at the server side.

Remarks:

None.

GetServerCrsCollection()

This method returns the projected or geographic coordinate reference systems to be used.

public Collection<string> GetServerCrsCollection()

Returns

Collection<string>

GetServerExceptionFormats()

This method returns the exception format at the server side.

public Collection<string> GetServerExceptionFormats()

Returns

Collection<string>
The exception format at the server side.

Remarks:

None.

GetServiceVersion()

This API gets the WMS server version of the service.

public string GetServiceVersion()

Returns

string
Returns a string reflecting the version of the service in WMS.

GetServiceBaseUrl()

This API gets the WMS base url of the service.

public string GetServiceBaseUrl()

Returns

string
Returns a string reflecting the WMS base url.

GetServerFeatureInfoFormats()

This API gets the WMS server FeatureInfo formats of the service.

public Collection<string> GetServerFeatureInfoFormats()

Returns

Collection<string>
This API returns the FeatureInfo formats supported on the server-side.

GetServerCapabilitiesXml()

This API gets the GetCapabilities document of the service.

public string GetServerCapabilitiesXml()

Returns

string
This API returns the GetCapabilities document of the service.

GetRequestUrl(RectangleShape, int, int)

Get the request URL from the client to the WMS.

public string GetRequestUrl(RectangleShape worldExtent, int canvasWidth, int canvasHeight)

Parameters

worldExtent RectangleShape
The world extent requested by the client to get the map.

canvasWidth int
The returning map width, as well as the drawing view width.

canvasHeight int
The returning map height, as well as the drawing view height.

Returns

string
The request URL from the client to the WMS.

GetRequestUrlCore(RectangleShape, int, int)

Provides the overridable implementation that returns request URL for the specified parameters.

protected string GetRequestUrlCore(RectangleShape worldExtent, int canvasWidth, int canvasHeight)

Parameters

worldExtent RectangleShape
The world extent represented by the canvas during the drawing session.

canvasWidth int
The canvas width.

canvasHeight int
The canvas height.

Returns

string
A string result.

OpenAsyncCore(CancellationToken)

This method opens the RasterSource so that it is initialized and ready to use.

protected Task OpenAsyncCore(CancellationToken cancellationToken)

Parameters

cancellationToken CancellationToken

Returns

Task
None

Exceptions

InvalidOperationException
In the event you attempt to call this method on an image source which has already been opened, it will throw an InvalidOperationException.

Remarks:

This protected virtual method is called from the concrete public method Open. The Open method plays an important role, as it is responsible for initializing the RasterSource. Most methods on the RasterSource will throw an exception if the state of the RasterSource is not opened. When the map draws each layer, it will open the RasterSource as one of its first steps; then, after it is finished drawing with that layer, it will close it. In this way, we are sure to release all resources used by the RasterSource.

When implementing this abstract method, consider opening files for file-based sources, connecting to databases in the database-based sources and so on. You will get a chance to close these in the Close method of the RasterSource.

CloseAsyncCore(CancellationToken)

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

protected Task CloseAsyncCore(CancellationToken cancellationToken)

Parameters

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task
A task that represents the asynchronous operation.

GetBoundingBoxCore()

This method returns the bounding box of the RasterSource.

protected RectangleShape GetBoundingBoxCore()

Returns

RectangleShape
The bounding box of the RasterSource.

Exceptions

InvalidOperationException
In the event you attempt to call this method on an image source which has not been opened, it will throw an InvalidOperationException.

Remarks:

This method returns the bounding box of the RasterSource.

DrawAsyncCore(GeoCanvas, Collection<SimpleCandidate>)

Provides the overridable implementation that asynchronously draws onto and appends any label candidates to .

protected Task DrawAsyncCore(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

canvas GeoCanvas
The to draw to.

labelsInAllLayers Collection<SimpleCandidate>
A shared collection that receives label candidates generated during drawing.

Returns

Task
A task that represents the asynchronous operation.

BuildWmsGetFeatureInfoUri(ScreenPointF, string, int)

Performs build WMS get feature info URI.

protected string BuildWmsGetFeatureInfoUri(ScreenPointF screenPointF, string infoFormat, int maxFeatures)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

infoFormat string
The info format.

maxFeatures int
The max features.

Returns

string
A string result.

GetFeatureInfoAsync(ScreenPointF, int, CancellationToken)

Returns feature info async from the underlying data source.

public Task<Dictionary<string, Collection<Feature>>> GetFeatureInfoAsync(ScreenPointF screenPointF, int maxFeatures, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

maxFeatures int
The max features.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

GetFeatureInfoAsync(ScreenPointF, CancellationToken)

Returns feature info async from the underlying data source.

public Task<Dictionary<string, Collection<Feature>>> GetFeatureInfoAsync(ScreenPointF screenPointF, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

GetFeatureInfoAsync(ScreenPointF, string, CancellationToken)

Returns feature info async from the underlying data source.

public Task<Dictionary<string, Collection<Feature>>> GetFeatureInfoAsync(ScreenPointF screenPointF, string infoFormat, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

infoFormat string
The info format.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

GetFeatureInfo(ScreenPointF, int, CancellationToken)

Returns feature info from the underlying data source.

public Task<Dictionary<string, Collection<Feature>>> GetFeatureInfo(ScreenPointF screenPointF, int maxFeatures, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

maxFeatures int
The max features.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

GetFeatureInfoAsync(ScreenPointF, string, int, CancellationToken)

Returns feature info async from the underlying data source.

public Task<Dictionary<string, Collection<Feature>>> GetFeatureInfoAsync(ScreenPointF screenPointF, string infoFormat, int maxFeatures, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

infoFormat string
The info format.

maxFeatures int
The max features.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

GetFeatureInfoAsyncCore(ScreenPointF, string, int, CancellationToken)

Provides the overridable implementation that returns feature info async from the underlying data source.

protected Task<Dictionary<string, Collection<Feature>>> GetFeatureInfoAsyncCore(ScreenPointF screenPointF, string infoFormat, int maxFeatures, CancellationToken cancellationToken)

Parameters

screenPointF ScreenPointF
The screen point, in pixels.

infoFormat string
The info format.

maxFeatures int
The max features.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Dictionary<string, Collection<Feature>>>
A task that represents the asynchronous operation and provides the result.

DownloadImageAsyncCore(double, double, double, RectangleShape, GeographyUnit, CancellationToken)

Provides the overridable implementation that performs download image async.

protected Task<Byte[]> DownloadImageAsyncCore(double width, double height, double scaleFactor, RectangleShape extent, GeographyUnit mapUnit, CancellationToken cancellationToken)

Parameters

width double
The width, in pixels.

height double
The height, in pixels.

scaleFactor double
The scale factor to apply.

extent RectangleShape
The world extent represented by the canvas during the drawing session.

mapUnit GeographyUnit
The map unit used for the drawing session.

cancellationToken CancellationToken
A cancellation or authentication token, depending on context.

Returns

Task<Byte[]>
A task that represents the asynchronous operation and provides the result.

GetRasterContentTypeCore()

WMS layers typically provide cartographic content.

protected RasterContentType GetRasterContentTypeCore()

Returns

RasterContentType

Rx8=(HttpRequestMessage, CancellationToken)

internal Task<Dictionary<string, Collection<Feature>>> Rx8=(HttpRequestMessage request, CancellationToken cancellationToken)

Parameters

request HttpRequestMessage

cancellationToken CancellationToken

Returns

Task<Dictionary<string, Collection<Feature>>>

SB8=(XmlDocument)

internal Dictionary<string, Collection<Feature>> SB8=(XmlDocument xmlDocument)

Parameters

xmlDocument XmlDocument

Returns

Dictionary<string, Collection<Feature>>

Events

RequestedImageException

This event is called after the image request done with some OnSendingWebRequest.

public event EventHandler<RequestedImageExceptionEventArgs> RequestedImageException;

Remarks:

This event is called before sending the request for raster image.
It is typical that user want to get the url of request and modify it according to their requirements. For example, user could create a signature for it, and verify it on the server side.

SendingHttpRequest

Occurs before an HTTP request is dispatched so callers can inspect or cancel it.

public event EventHandler<SendingHttpRequestMessageEventArgs> SendingHttpRequest;

ReceivedHttpResponse

Occurs after an HTTP response is received.

public event EventHandler<ReceivedHttpResponseMessageEventArgs> ReceivedHttpResponse;

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;