GeoMedia code snippet to apply a workspace spatial filter

In GeoMedia, a Spatial filter is a means to improve the application performance by reducing the amount of spatial data for display and processing. Typically, this is done using an arbitrary polygon as the spatial filter boundary.

The following C# code snippet can be used as a method in a driving GeoMedia type custom application to apply a rectangular spatial filter to the GeoMedia workspace.

using GMService = Intergraph.GeoMedia.GMService;

using PService = Intergraph.GeoMedia.PService;

using PBasic = Intergraph.GeoMedia.PBasic;

using PClient = Intergraph.GeoMedia.PClient;

//...etc....

private GeoMedia.Application _application = null;

//...etc...

public void ApplyWorkspaceSpatialFilter(PBasic.point lowerLeftPoint, PBasic.point upperRightPoint)

{

//Declare variables

PBasic.PolygonGeometry polygon;

PBasic.point pnt;

object objBlob;

PClient.GeometryStorageService storageSvc;

GMService.ApplySpatialFilterService spatFilterSvc;

//Create a new instance of the ApplySpatialFilterService

spatFilterSvc = new GMService.ApplySpatialFilterService(); 

//Create a new polygonGeometry object for the spatial filter polygon

polygon = (PBasic.PolygonGeometry) _application.CreateService("GeoMedia.PolygonGeometry");

//Create a new GeoMedia point object

pnt = (PBasic.point)_application.CreateService("GeoMedia.point");

//Populate the spatial filter polygon object with the bounding rectangle

pnt.X = lowerLeftPoint.X;

pnt.Y = lowerLeftPoint.Y;            

polygon.Points.Add ( pnt, null);

pnt.X = lowerLeftPoint.X;

pnt.Y = upperRightPoint.Y;

polygon.Points.Add (pnt, null);

pnt.X = upperRightPoint.X;

pnt.Y = upperRightPoint.Y;

polygon.Points.Add (pnt, null);

pnt.X = upperRightPoint.X;

pnt.Y = lowerLeftPoint.Y;

polygon.Points.Add (pnt, null);

pnt.X = lowerLeftPoint.X;

pnt.Y = lowerLeftPoint.Y;

polygon.Points.Add (pnt, null);

//Create a new instance of the GeometryStorageService object

storageSvc = (PClient.GeometryStorageService) _application.CreateService("GeoMedia.GeometryStorageService");

//Convert the polygonGeometry object into a blob

storageSvc.GeometryToStorage(polygon, out objBlob);

//Assign the polygonGeometry to the SpatialFilterService object and apply the spatial filtering to

//the GeoMedia application workspace

spatFilterSvc.Application = this._application;

spatFilterSvc.SpatialFilterOperator = PClient.GConstants.gdbTouches;

spatFilterSvc.SpatialFilterGeometry = objBlob;

spatFilterSvc.SpatialFilterName = "SpatialFilter1";

spatFilterSvc.UseGeometryMBR = false;

spatFilterSvc.Execute();

//Free up resources

objBlob = null;

if (spatFilterSvc != null) Marshal.FinalReleaseComObject(spatFilterSvc);

if (storageSvc != null) Marshal.FinalReleaseComObject(storageSvc);

if (polygon != null) Marshal.FinalReleaseComObject(polygon);

if (pnt != null) Marshal.FinalReleaseComObject(pnt);

}