DataQueryQueryPolygonsAtPoint Method (LatLon, String, Double, CancellationToken) |  |
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Gets an array of Polygon objects that
encapsulate the given LatLon. This method can be used to find
polygons (such as golf courses, parks, airports, political/geographical entities and bodies of water)
at a given location. See example.
Namespace: Telogis.GeoBase
Assembly: geobase.net (in geobase.net.dll) Version: 4.99.0.0
Syntaxpublic static Polygon[] QueryPolygonsAtPoint( LatLon loc, string tableName, double simplificationLevel, CancellationToken token )
Parameters
- loc
- Type: Telogis.GeoBaseLatLon
A LatLon location to query. - tableName
- Type: SystemString
The name of the polygon table to query (this specifies the PolygonType to return). - simplificationLevel
- Type: SystemDouble
Level used to simplify results, given as meters per pixel. - token
- Type: Telogis.GeoBase.ConcurrencyCancellationToken
A CancellationToken that can be used to cancel the query, causing a DataQueryCanceledException to be thrown.
Return Value
Type: PolygonAn array of Polygons matching the specified type.
RemarksMap features are stored in tables, named according to type. Developers with custom data should avoid using the table names in the list below.
| Pre-defined polygon query tables |
|---|
| all |
| countries |
| states |
| counties |
| islands |
| cities |
| airports |
| runways |
| cemeteries |
| hospitals |
| industrial |
| major_parks |
| state_parks |
| parks |
| shopping |
| sports |
| universities |
| golf_courses |
| native |
| military |
| buildings |
| oceans |
| bays |
| water |
ExamplesC#
// // Get the golf course (if one exists) at the given location... // LatLon loc = new LatLon(33.919432,-118.31181); // location in Los Angeles, USA Polygon[] gcs = DataQuery.QueryPolygonsAtPoint(loc, "golf_courses", 1); Console.WriteLine("There is " + gcs.Length + " golf course at the location " + loc.ToString()); CancellationToken token = new CancellationToken(); // // Get all polygons at the given location... // gcs = DataQuery.QueryPolygonsAtPoint(loc, "all", 1, token); Console.WriteLine("There are a total of " + gcs.Length + " polygons at the location " + loc.ToString()); int counter = 1; foreach (Polygon p in gcs) { Console.WriteLine("\t" + (counter++) + ") " + p.Name); }
The above code snippet produces the following output:
See Also