Changes between Initial Version and Version 1 of CodeSnippets/GetDynamicExtents

Timestamp:

Oct 15, 2008, 10:01:17 AM (16 years ago)

Author:

jbirch

Comment:

--

CodeSnippets/GetDynamicExtents

@@ +1 @@
+[[PageOutline]]
+
+This page is an FDO Code Snippet.  Visit the CodeSnippets page to view more!
+
+= Calculating Dynamic Extents =
+
+The easiest and most efficient way of determining extents from a provider that supports dynamic extents is to use the !GetSpatialContext command.
+
+== C# Example ==
+
+{{{
+#!cpp
+
+  using OSGeo.FDO.Connections;
+  using OSGeo.FDO.Commands.SpatialContext;
+  using OSGeo.FDO.Geometry;
+
+  IGetSpatialContexts getSpatialContexts = connection.CreateCommand(CommandType.CommandType_GetSpatialContexts) as IGetSpatialContexts;
+  ISpatialContextReader reader = getSpatialContexts.Execute(); 
+  IGeometry geom = null; 
+  byte[] extentAsByteArr = null; 
+  string extentAsText = null; 
+  FgfGeometryFactory geomFactory = new FgfGeometryFactory(); 
+
+  while (reader.ReadNext()) {
+    extentAsByteArr = reader.GetExtent();
+    // if extent type is dynamic and no geometries have been added
+    // the extent can be null
+    if (extentAsByteArr != null)
+    {
+      geom = geomFactory.CreateGeometryFromFgf(extentAsByteArr);
+      extentAsText = geom.Text;
+    }
+    else
+    {
+      extentAsText = "No extent found";
+    }
+  }
+
+}}}
+
+== C++ Example ==
+
+{{{
+#!cpp
+
+  Please add here!
+
+}}}
+
+== Contributors ==
+
+ * Donald Cameron
+