Querying in the GIS Framework

Modified on Monday, 18 July 2011 08:42 AM by 156.75.200.64 — Categorized as: Query

The GIS Framework provides interfaces that must be implemented by data sources that need to be plugged into the framework so that they will work seamlessly with the various components. All query operations return a set of features grouped by feature type.

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QueryManager
   Properties
   Operations
IQueryableDataSource
   Inteface Definition
   Properties
   Operations
FeatureType
   Properties
Feature

QueryManager¶

The FDOT.GIS.Client.Domain.QueryManager class provides and API for issuing queries against the data sources registered for a virtual application. Data sources must implement the FDOT.GIS.Client.Domain.IQueryableDataSource interface which provides the ability to Query, Identify or Find data features.

Properties¶

Name	Type	Description
RegisteredDataSources	IEnumerable	The set of registered data sources

Operations¶

Name	Description
RegisterDataSource	Register a data source. Note that queryable map services are automatically registered as data sources when the layer is initialized.
UnregisterDataSource	Remove a data source.
GetDataSource	Retrieve a data source by id. Returns null if not found.
GetDataSourceForFeatureType	Retrieve a data source by feature type. Throws an exception if no data source is found for the feature type
ExecuteQuery	Executes a query against the correct data source for the given feature type and provides the results to a callback function
ExecuteIdentify	Executes a search across all registered data sources for features that touch the provided geometry and provides the results to a callback function

IQueryableDataSource¶

Objects implementing the FDOT.GIS.Client.Domain.IQueryableDataSource represent a data source that can be queried through the GIS framework.

Inteface Definition¶

 public interface IQueryableDataSource
{
    string Id { get; }
    IEnumerable<FeatureType> FeatureTypes { get; }
    void Query(QueryParameters parameters, string startingId, Action<QueryResult> callback);
    void Identify(DataContracts.Geometry geometry, Action<IDictionary<FeatureType, ICollection<Feature>>> callback);
    void Find(FindParameters parameters, Action<ICollection<QueryResult>> callback);
}

Properties¶

Name	Type	Description
Id	string	A unique data source identifier
FeatureTypes	IEnumerable	The set of feature types this data source can query

Operations¶

Name	Description
Query	Return features from a specific feature type that match a given set of attribute and geometry criteria.
Identify	Search across feature types for any features that are touched by a given geometry.
Find	Search across feature types for any features that match a given set of attribute criteria.

FeatureType¶

The FDOT.GIS.Client.Domain.FeatureType class describes a feature type. It provides information regarding the data attributes the features will possess and whether they have associated geometry.

Properties¶

Name	Type	Description
Id	string	A feature type identifier
Name	string	The display name for the feature type
Description	string	Some text describing the data and purpose of the feature type
Attributes	ICollection	The attributes that features of this feature type will have.
HasGeometry	bool	A flag indicating whether the features of this feature type will have associated geometry.
GeometryType	FDOT.GIS.DataContracts.Enums.GeometryTypes	The Geometry type for the geometry object associated with the features from this feature type.

Feature¶

See Main Article Feature

The FDOT.GIS.Client.Domain.Feature class represents an individual feature and contains all data attributes and associated geometry.