SortOperator Class
Sorts incoming features and passes them on in a different order.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CEOperators assembly)
Syntax
public class SortOperator : UnaryOperatorRemarks
The operator can be used to reorder the passing features according to some sort criteria. This could be useful in some cases to control the rendering order of features in a 2D layer. It may not be as useful in 3D though, since objects closer to the camera will always be visible in front of objects further back, regardless of the order they are rendered.
The sorting is done by calculating a key value for each feature using the expression specified by Key, and then sort the features according to the key values. The feature with the lowest value will be returned first and rendered first by the layer, i.e. features with high values will be drawn on top of features with lower values.
The values will be the result of evaluating the key expression, i.e. either null or an integer, double, bool, string or atom value.
null is always less than any other value.
Integers, doubles and bools are compared numerically (bools are converted to 0.0 or 1.0).
Strings and atoms are compared as strings. Note that string comparison is done by just comparing the byte values of the UTF-8 strings used internally.
If a string or atom is compared to a numeric value, the string is always greater.
Two features with equal values will keep their individual order.
Additionally, if the ReverseOrder property is True, the entire list of features will reversed, after the sorting has been done. You can leave the key expression empty and just set ReverseOrder to True, this will in effect just reverse the order of the features, without sorting them first.
The SortOperator will currently not work in layers with dynamic caching. This is because layers with dynamic caching expects the features to arrive in the same order they were returned from the MemoryDataSet. If you try to use a SortOperator like this, an exception will be thrown.
If you try to use the operator under a TileLayer, it will work, but the rendering order of overlapping feature visualization from different tiles will be undefined.
Inheritance Hierarchy
System.Object (not available in C#)
EngineObject
Operator
UnaryOperator
SortOperator
Platforms
Windows, Linux, Android
SortOperator Members
The SortOperator type has the following members.
Constructors
| Name | Description |
|---|---|
| SortOperator | Initializes a new instance of the SortOperator class. |
Properties
| Name | Description |
|---|---|
| Description | Gets or sets a short description of the operator. Inherited from Operator |
| DisplayName | Gets or sets a display name for the operator. Inherited from Operator |
| Input | Gets or sets the input operator, from which this operator reads features. Inherited from UnaryOperator |
| IsDisposed | Gets a value that tells whether the current SortOperator has been disposed. Inherited from EngineObject |
| IsoMetadataDocument | Gets or sets the path to an ISO 19139 metadata document for the operator. Inherited from Operator |
| Key | Gets or sets the expression used to calculate the key value for a feature. |
| Name | Gets or sets the name of the operator. Inherited from Operator |
| NativeHandle | Gets the native Carmenta Engine kernel object the current SortOperator represents. Inherited from EngineObject |
| ReverseOrder | Gets or sets a value specifying if the order of the features should be reversed. |
| IUserProperties.UserProperties | Gets the AttributeSet that contains the user properties. Inherited from IUserProperties |
Methods
| Name | Description |
|---|---|
| Clone | Creates a copy of an object. Inherited from EngineObject |
| Dispose | Releases the reference to the native Carmenta Engine kernel instance the EngineObject represents. Inherited from EngineObject |
| Equals | Determines whether this instance is equal to another. Inherited from EngineObject |
| FindChildObject | Overloaded. Finds the child object with the specified name. Inherited from Operator |
| FlushCache | Marks the layer as flushed which will release cached resources during the next update. Inherited from Operator |
| GetChildObjects | Overloaded. Gets the child objects of the current object. Inherited from Operator |
| GetFeatures | Overloaded. Gets features from the operator chain. Inherited from Operator |
| GetLocalizedDescription | Gets a localized version of the operator description in a specific language. Inherited from Operator |
| GetLocalizedDisplayName | Gets a localized version of the operator display name in a specific language. Inherited from Operator |
| GetLocalizedIsoMetadataDocument | Gets the path to an ISO 19139 metadata document for a specific language. Inherited from Operator |
| GetRasterFeature | Overloaded. Gets raster features from the operator chain and merges them into a single raster. Inherited from Operator |
| HasLocalizedDescription | Checks if a localized version of the operator description is available in a specific language. Inherited from Operator |
| HasLocalizedDisplayName | Checks if a localized version of the operator display name is available in a specific language. Inherited from Operator |
| HasLocalizedIsoMetadataDocument | Checks if an ISO 19139 metadata document is available for a specific language. Inherited from Operator |
| SetLocalizedDescription | Sets a operator description in a specific language. Inherited from Operator |
| SetLocalizedDisplayName | Sets a operator display name in a specific language. Inherited from Operator |
| SetLocalizedIsoMetadataDocument | Sets the path to an ISO 19139 metadata document for the operator, for a specific language. Inherited from Operator |