ArcGIS Engine 10 开发手册(4-20)空间查询

什么是空间查询

空间查询可以说是两步过滤，属性过滤和空间过滤，既然有空间过滤， 空间查询体 现 在 ISpatialFilter.Geometry 和 ISpatialFilter.SpatialRel 上，那么这个接口的 Geometry 和 spatialrel 属 性是必须的。众所周知 ArcMap 的空间查询是非常丰富的，而 ArcGIS Engine 可以毫无保留的实现 ArcMap 所能提供的全部空间查询，对于 ArcGIS Engine 来说这些空间查询只是 ISpatialFilter 的参数，而这些参 数都是常量，如下表所示：

查询矩形范围内的点要素（示例）

public ESRI.ArcGIS.Geodatabase.IFeatureCursor GetAllFeaturesFromPointSearchInGeoFeatureLayer (ESRI.ArcGIS.Geometry.IEnvelope pEnvelope, IPoint pPoint, IFeatureClass pFeatureClass)
{
  if (pPoint == null || pFeatureClass == null)
  {
    return null;
  }

  //ITopologicalOperator pTopo = pPoint as ITopologicalOperator;

  //IGeometry pGeo = pTopo.Buffer(pSearchTolerance);

  System.String pShapeFieldName = pFeatureClass.ShapeFieldName;
  ESRI.ArcGIS.Geodatabase.ISpatialFilter pSpatialFilter = new ESRI.ArcGIS.Geodatabase.SpatialFilterClass ();
  pSpatialFilter.Geometry = pEnvelope;

  pSpatialFilter.SpatialRel = ESRI.ArcGIS.Geodatabase.esriSpatialRelEnum.esriSpatialRelEnvelopeIntersects;

  pSpatialFilter.GeometryField = pShapeFieldName;

  ESRI.ArcGIS.Geodatabase.IFeatureCursor pFeatureCursor = pFeatureClass.Search (pSpatialFilter, false);

  return pFeatureCursor;
}

IMap map = this.axMapControl1.Map;
ISelection selection = map.FeatureSelection;

IEnumFeatureSetup pEnumFeatureSetup = (IEnumFeatureSetup) selection;
pEnumFeatureSetup.AllFields = true;

IEnumFeature pEnumFeature = (IEnumFeature) selection;
IFeature feature = pEnumFeature.Next ();

while (feature != null)
{
  string a = Convert.ToString (feature.get_Value (feature.Fields.FindField ("dfd")));
  feature = pEnumFeature.Next ();
}

ArcGIS Engine 10 开发手册全集

ArcGIS Engine 10 开发手册全集： ArcGIS Engine 10 开发手册