--- title: "River" language: "en" type: "Entity" summary: "Notable rivers, creeks, brooks and similar freshwater bodies." canonical_url: "https://reference.wolfram.com/language/ref/entity/River.html" source: "Wolfram Language Documentation" related_guides: - title: "Entity Types" link: "https://reference.wolfram.com/language/guide/EntityTypes.en.md" --- # River Notable rivers, creeks, brooks and similar freshwater bodies. [Related Interpreter](https://reference.wolfram.com/language/ref/interpreter/River.en.md) Entity["River", name] or Entity[...] represents an entity of type "River". Entity[...][prop] gives the value of a specified property. Entity[...][{propi, …}] gives the value of a list of properties. EntityClass["River", {propi -> speci, …}] represents a class of entities with values of propi defined by speci. ## Sample Entities * Entity["River", "Amazon::n9532"]Entity["River", "Amur::9998h"]Entity["River", "ColumbiaRiver::5b5cq"]Entity["River", "Danube::k6mff"]Entity["River", "Ganges::34vq3"]Entity["River", "Mekong::3b95f"]Entity["River", "Nile::h43n2"]Entity["River", "Sepik::3n554"]Entity["River", "Volga::77km4"]Entity["River", "Zambezi::cr8qm"]**…** ## Properties | | | | -------------------- | ---------------------- | | AlternateNames | alternate names | | AverageDischarge | average discharge | | Countries | countries | | DrainageArea | drainage area | | EasternmostPoint | easternmost point | | EntityClasses | entity classes | | EntityTypeList | entity type list | | HighestPoint | highest point | | Image | image | | LeftBankTributaries | left bank tributaries | | Length | length | | LowestPoint | lowest point | | MaximumDischarge | maximum discharge | | MinimumDischarge | minimum discharge | | Name | name | | NorthernmostPoint | northernmost point | | Outflow | outflow | | OutflowLocation | outflow location | | OutflowPosition | outflow coordinates | | RightBankTributaries | right bank tributaries | | SourceEntity | source | | SourceLocation | source location | | SourcePosition | source coordinates | | SouthernmostPoint | southernmost point | | WesternmostPoint | westernmost point | ## Details * ``"River"`` entities include bodies of flowing water throughout the world. * Some properties are available for the ``"River"`` entity type as a whole and can be given using the form ``EntityValue["River", property]``. Such properties include: | | | | ----------------------------- | ------------------------------------------------------------------ | | "Properties" | the list of available properties | | "PropertyCanonicalNames" | the standard names of available properties | | "SampleEntities" | a sample list of available entities (typically of length 10) | | "SampleEntityClasses" | a sample list of available entity classes (typically of length 10) | | "EntityCount" | number of entities available | | "Entities" | the list of available entities | | "EntityCanonicalNames" | the standard names of available entities | | "EntityClasses" | the list of available entity classes | | "EntityClassCanonicalNames" | the standard names of available entity classes | | "PropertyClasses" | the list of available property classes | | "PropertyClassCanonicalNames" | the standard names of available property classes | | "PropertyCount" | number of properties available | * The following annotations can be used in the third argument of ``EntityValue["River", property, annotation]`` : | | | | --- | --- | | "Source" | source information for the property | | "Date" | the date associated with the entity-property value (if any) | | "EntityAssociation" | an association of entities and entity-property values | | "PropertyAssociation" | an association of properties and entity-property values | | "EntityPropertyAssociation" | an association in which the specified entities are keys, and values are a nested association of properties and entity-property values | | "PropertyEntityAssociation" | an association in which the specified properties are keys, and values are a nested association of entities and entity-property values | | "Dataset" | a dataset in which the specified entities are keys, and values are an association of property names and entity-property values | * The following annotations can be used in the second argument of ``EntityValue[property, annotation]`` : | | | | ------------------------ | --------------------------------------------------------------- | | "Qualifiers" | the list of possible qualifiers for the property | | "QualifierValues" | the list of possible values that can be given to each qualifier | | "DefaultQualifierValues" | the list of default values for the property's qualifiers | | "Description" | a brief textual description of the property | | "Definition" | a detailed textual definition of the property | | "PhysicalQuantity" | the physical quantity associated with the entity-property value | | "Unit" | the unit associated with the entity-property value | * A qualifier value of ``Automatic`` indicates that an applicable format of values can be used; e.g. for the ``"Date"`` qualifier, this includes a proper date or date span. --- ## Examples (7) ### Basic Examples (4) Use ctrl+= for entity discovery: ```wl In[1]:= \[FreeformPrompt]["chang jiang river"] Out[1]= Entity["River", "Yangtze::wqwy2"] ``` --- Find a property value for an entity: ```wl In[1]:= Entity["River", "Mekong::3b95f"]["Countries"] Out[1]= {Entity["Country", "Laos"], Entity["Country", "Thailand"], Entity["Country", "China"], Entity["Country", "Cambodia"], Entity["Country", "Vietnam"], Entity["Country", "Myanmar"]} ``` --- Retrieve a dataset of all available properties for an entity: ```wl In[1]:= Entity["River", "Volga::77km4"]["Dataset"]//DeleteMissing Out[1]= Dataset[Association[EntityProperty["River", "AverageDischarge"] -> Quantity[285342.5071096278261393309`4., "Feet"^3/"Seconds"], EntityProperty["River", "Countries"] -> {Entity["Country", "Russia"], Entity["Country", "Kazakhstan"]}, Enti ... WesternmostPoint"] -> GeoPosition[{56.934612027504045, 32.96744541881367}], EntityProperty["Thing", "EntityClasses"] -> {}, EntityProperty["Thing", "EntityTypeList"] -> {EntityType["River"]}, EntityProperty["Thing", "Name"] -> "Volga"]] ``` --- Find rivers that have the largest drainage areas: ```wl In[1]:= EntityClass["River", "DrainageArea" -> TakeLargest[5]]//EntityList Out[1]= {Entity["River", "Amazon::n9532"], Entity["River", "RioDeLaPlata::5227y"], Entity["River", "Congo::zqkh9"], Entity["River", "Nile::h43n2"], Entity["River", "Parana::jkyk5"]} ``` ### Scope (3) Retrieve multiple properties of a river: ```wl In[1]:= Entity["River", "Euphrates::22y69"][{"Image", "Countries", "Outflow"}] Out[1]= {[image], {Entity["Country", "Iraq"], Entity["Country", "Turkey"], Entity["Country", "Iran"], Entity["Country", "Syria"]}, {Entity["River", "ShattAl-Arab::h6zy5"]}} ``` --- Get quantitative properties of a river: ```wl In[1]:= EntityValue[Entity["River", "Amazon::n9532"], {"Length", "AverageDischarge", "DrainageArea"}, "PropertyAssociation"] Out[1]= <|"Length" -> Quantity[3976.7756303189371465123`3., "Miles"], "AverageDischarge" -> Quantity[7.7339120120060015469789505`6.*^6, "Feet"^3/"Seconds"], "DrainageArea" -> Quantity[2.669896426321013*^6, "Miles"^2]|> ``` --- Retrieve data for the five rivers with the highest drainage area: ```wl In[1]:= EntityValue[EntityClass["River", "DrainageArea" -> TakeLargest[5]], {"Image", "Countries"}, "Dataset"] Out[1]= Dataset[«1»] ``` ## See Also * [`Island`](https://reference.wolfram.com/language/ref/entity/Island.en.md) * [`Lake`](https://reference.wolfram.com/language/ref/entity/Lake.en.md) * [`Waterfall`](https://reference.wolfram.com/language/ref/entity/Waterfall.en.md) * [`Ocean`](https://reference.wolfram.com/language/ref/entity/Ocean.en.md) * [`UnderseaFeature`](https://reference.wolfram.com/language/ref/entity/UnderseaFeature.en.md) * [`Reef`](https://reference.wolfram.com/language/ref/entity/Reef.en.md) * [`Beach`](https://reference.wolfram.com/language/ref/entity/Beach.en.md) * [`Mountain`](https://reference.wolfram.com/language/ref/entity/Mountain.en.md) * [`Volcano`](https://reference.wolfram.com/language/ref/entity/Volcano.en.md) * [`Glacier`](https://reference.wolfram.com/language/ref/entity/Glacier.en.md) * [`EarthImpact`](https://reference.wolfram.com/language/ref/entity/EarthImpact.en.md) * [`Desert`](https://reference.wolfram.com/language/ref/entity/Desert.en.md) * [`Forest`](https://reference.wolfram.com/language/ref/entity/Forest.en.md) * [`River`](https://reference.wolfram.com/language/ref/interpreter/River.en.md) * [`ComputedRiver`](https://reference.wolfram.com/language/ref/interpreter/ComputedRiver.en.md) * [`River`](https://reference.wolfram.com/language/ref/textcontent/River.en.md) ## Related Guides * [Entity Types](https://reference.wolfram.com/language/guide/EntityTypes.en.md) ## History * [Introduced in 2019 (12.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn120.en.md)